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PLOS Neglected Tropical Diseases logoLink to PLOS Neglected Tropical Diseases
. 2021 Feb 5;15(2):e0009085. doi: 10.1371/journal.pntd.0009085

Weaknesses in primary health care favor the growth of acquired syphilis

Marquiony Marques dos Santos 1,2,3,*, Tatyana Maria Silva de Souza Rosendo 1,4, Ana Karla Bezerra Lopes 1,2,3, Angelo Giuseppe Roncalli 1,4, Kenio Costa de Lima 1,2,4
Editor: Jorg Heukelbach5
PMCID: PMC7891733  PMID: 33544722

Abstract

Acquired syphilis is a sexually transmitted infection that affects the general population and has been growing in recent years in many countries. A study was developed aiming to analyze the trends of acquired syphilis associated with sociodemographic aspects and primary health care in Brazil, in the period from 2011 to 2019. This study used secondary data from the national notification systems of the 5570 Brazilian cities and a database of 37,350 primary health care teams, as well as socioeconomic and municipal demographic indicators. The trends of acquired syphilis at the municipal level were calculated from the log-linear regression, crossing them with variables of primary health care and sociodemographic indicators. Finally, a multiple model was built from logistic regression. 724,310 cases of acquired syphilis have been reported. In primary care units, 47.8% had partial coverage and 74.1% had health teams with poor or regular scores. 52.6% had rapid test for syphilis partially available. Male and female condoms are available in 85.9% and 62.9% respectively and 54.4% had penicillin available in the health facility. The increase in trends of acquired syphilis was associated with better availability of the rapid test; lower availability of male condoms; lower availability of female condoms; lower availability of benzathine penicillin; partial coverage of the teams in primary health care; limited application of penicillin in primary health care; higher proportion of teams classified as Poor/Regular in primary health care; higher proportion of women aged 10 to 17 years who had children; higher HDI; higher proportion of people aged 15 to 24 years who do not study, do not work and are vulnerable; and population size with more than 100,000 inhabitants. The following variables remained in the multiple model: not all primary health care teams apply penicillin; higher proportion of primary health care teams with poor/regular scores; population size >100000 inhabitants; partially available female condom. Thus, the weakness of primary health care linked to population size may have favored the growth of the acquired syphilis epidemic in Brazilian cities.

Author summary

Acquired syphilis is a sexually transmitted infection that continues to impact health services around the world. For decades, studies and public health policies in the fight against syphilis have focused on syphilis in pregnant women and congenital, mainly because of their importance in the health of women and children. However, the behavior of the epidemic in people aged over 13 years shows that the epidemic is comprehensive and challenging. The exponential increase in the syphilis epidemic in the general population is one of the most neglected in many parts of the world. Primary health care plays a fundamental role in the control of syphilis, but few studies have sought to analyze the impact of primary health care on the growth of acquired syphilis. Our work used two large databases of the national notification systems of the 5570 Brazilian cities and a database of 37,350 primary health care teams, as well as municipal sociodemographic indicators. Our results demonstrated several indicators that influence the growth of acquired syphilis, especially the most neglected, which can guide more effective strategies to fight the syphilis epidemic in several countries.

Introduction

Syphilis is a sexually transmitted infection (STI) resulting from contamination by the bacterium Treponema pallidum. Although syphilis was discovered hundreds of years ago and its form of diagnosis and treatment is widely known, the epidemic grows exponentially in many countries and challenges, mainly, primary health care services [13].

According to estimates of the WHO, more than 6 million people aged between 15 and 49 years are infected with syphilis each year worldwide. In addition, the disease is responsible for more than 300,000 fetal and neonatal deaths [1]. In the regions of the Americas, these numbers remain high and impact on health services, especially in countries with limited resources [4,5].

The increase in syphilis in these countries occurs in several population groups, such as pregnant women and newborns. However, the highest rates of the disease are observed in the general population that is not part of these groups, characterizing acquired syphilis [1]. In Brazil, the highest rates of syphilis are also observed in relation to acquired syphilis, making it a neglected group, such as men who have sex with men, sex workers and transgender people.

According to the 2019 Brazilian epidemiological report, acquired syphilis increased from 2.0 cases per 100,000 inhabitants in 2010 to 58.1 cases per 100,000 inhabitants in 2017 [6]. This represents a 2800% increase in the detection rate acquired of syphilis in the country. This growth of the epidemic is influenced by the beginning of late compulsory notification in the general population; however, the structure and organization of primary health care services directly influence disease control strategies [7].

Since syphilis bacterium infection is among the most common STIs, whose transmission occurs mainly through the unprotected sexual act, the actions of condom distribution, the offer of rapid tests for syphilis, adequate treatment and availability of penicillin, are some of the fundamental aspects for combating the epidemic of this STI. In addition to these actions, access, coverage and quality of primary health care may be related to the growth of the disease [8]. Nevertheless, few studies in the literature sought to evaluate the relationship between primary health care indicators, sociodemographic data of the cities and their association with the trends of acquired syphilis.

The significant increase in acquired syphilis shows important flaws in health services and its growth has aroused worldwide concern in recent years. Thus, knowing the trends of acquired syphilis in Brazil and identifying the factors related to primary health care and the sociodemographic structure of the cities can guide new strategies for health promotion and disease prevention, as well as direct resources that significantly influence the reduction of the epidemic. Thus, the aim of this study is to analyze the trends of acquired syphilis associated with sociodemographic aspects and primary health care in Brazil, in the period from 2011 to 2018.

Methods

A cross-sectional study was developed to understand the factors related to the trends of acquired syphilis in the period from 2011 to 2019. This study is part of the Brazilian effort to understand the syphilis epidemic and set goals to reduce it, through the project “No Syphilis” whose objective is to reduce acquired syphilis and eliminate congenital syphilis in Brazil [9]. The chosen data collection period is due to the effective notification of acquired syphilis in Brazil, which became compulsory in 2010.

The annual rates of acquired syphilis in the 5570 Brazilian cities were calculated, obtaining them from the number of cases of acquired syphilis (ICD-10: 53.9) in individuals aged 13 years or more in the city, divided by the total local population of individuals in the same age group, multiplied by 100,000. The rates were collected through secondary data from public national health information systems, such as the Notifiable Diseases Information System (SINAN) and the Brazilian Institute of Geography and Statistics (IBGE).

From the annual rates of acquired syphilis, the dependent variable Average Annual Percent Change (AAPC)[10], was calculated, which represents the weighted average of the angular coefficients (W) of the underlying regression line, with the weights equal to the length of the measured interval (b) was calculated. The AAPC is the percentage value that summarizes the variation that occurred during the study period, that is, the number that represents the trend of acquired syphilis from each city.

The independent variables are related to data from Primary Health Care (PHC) from the research of the “National Program for Improvement of Access and Quality of Primary Care (PMAQ)”, third cycle. It is a public database, individualized and unidentified, with the objective of evaluating all PHC teams in Brazil. Of the 38,865 teams chosen for the PMAQ survey (S1 Table), teams that did not complete the questionnaire were excluded from the records, totaling 37,350 teams with adequate completion, which is equivalent to a percentage of 96.10%. The responses of the PHC teams were aggregated per cities [11]. The aggregate variables from the PMAQ used in the present study are described in Table 1.

Table 1. PHC-related variables of the PMAQ.

Question Description Categories
Rapid syphilis test always available? Assess the availability of rapid testing in PHC 1—Partially available
2—Fully Available
Male condom always available? Evaluates the availability of male condoms in PHC 1—Partially available
2—Fully Available
Female condom always available? Evaluates the availability of female condoms in PHC 1—Partially available
2—Fully Available
Sufficient benzyl penicillin (penicillin G) in PHC Evaluates the availability of penicillin in PHC 1—Partially available
2—Fully Available
Are there families discovered by PHC in the area surrounding the team’s territory? Evaluates PHC service coverage by teams, grouped by municipality 1 –Partial coverage
2 –Fully covered
Is benzyl penicillin (penicillin G) applied in the health unit? Evaluates whether PHC teams apply benzyl penicillin (penicillin G) in the health unit 1—Not all teams apply
2 –All teams apply
Proportion of PHC teams with Poor/Regular grades Proportion of PHC teams in the municipality with poor or regular grades, obtained from the degree of quality of the teams’ work measured in 532 quality standards 1 –Presence of PHC teams with poor / regular grades
2 –No PHC team has poor/regular grades

Socioeconomic and demographic variables were collected, such as Human Development Index (HDI), which is the geometric mean of the indexes of the dimensions Income, Education and Longevity; Gini index, which measures the degree of inequality according to per capita household income. Its value ranges from 0, when there is no inequality to 1, when inequality is maximum; proportion of people aged 15 to 24 who do not study, do not work and are vulnerable; proportion of mothers who are wage earners without complete primary education and with children under 15 years of age; total population in permanent private households, categorized into population size. Data related to socioeconomic and demographic municipal characterization were obtained from IBGE.

Data sources

The AAPC variable that represents the trends of acquired syphilis in each city was categorized: upward, static or downward trend. This theoretical categorization was important due to the characteristic of the AAPC variable, as well as the importance of understanding the factors that influence the upward trend of acquired syphilis in Brazilian cities. The sociodemographic quantitative variables were categorized based on the lowest p value. Then, to identify the association of categorized AAPC between the variables related to the PMAQ and the sociodemographic variables, the bivariate analysis was performed using the Chi-square test. Furthermore, the magnitude of the association was verified through the prevalence ratio for each of the independent variables in relation to the dependent variable, at a significance level of 95%.

To identify the independent factors associated with the AAPC of the upward trend of acquired syphilis, multiple logistic regression analysis was performed. For this, the Stepwise Forward Selection Procedure method was used, in which the variables that compose the model were grouped into blocks, ordering them according to their statistical significance.

The modeling was initiated by the most significant variables of the Chi-square method and, then, the other variables were added one by one, accepting a critical p value of <0.20 to compose the model. The permanence of the variable in the multiple analysis occurred through the likelihood ratio test, absence of multicollinearity, as well as its ability to improve the model through the Hosmer and Lemeshow test. Finally, the residues were analyzed to isolate cases that exert an undue influence on the model, causing little adherence. The data were analyzed using the Statistical Package for the Social Sciences (SPSS) 22.0 program and all analyses considered a significance level equal to 5%.

Results

From 2011 to 2019, there were 724,310 reported cases of acquired syphilis throughout Brazil. After descriptive analysis of PHC-related variables, the highest proportions are from the partially available rapid syphilis test (52.6%); fully available male condom (85.9%); fully available female condom (62.9%); partially available benzathine penicillin (71.4%); Coverage of PHC teams with partial coverage (47.8%); Application of penicillin in PHC, all teams apply (54.4%); and presence of Poor/Regular teams in PHC (74.1%) (Table 2).

Table 2. Distribution of frequency and proportions of variables related to the basic health service.

Category Frequency Percentage
Rapid syphilis test in PHC
Partially available 2930 52.6
Fully Available 2382 42.8
Male condom in PHC
Partially available 529 9.5
Fully Available 4783 85.9
Female condom in PHC
Partially available 1810 32.5
Fully Available 3502 62.9
Benzyl penicillin (penicillin G) in PHC
Partially available 3977 71.4
Fully Available 1335 24.0
Coverage of PHC teams
Partial coverage 2665 47.8
Fully covered 2645 47.5
Application of penicillin in PHC
Not all teams apply 2282 41.0
All teams apply 3028 54.4
Poor / regular grades teams in PHC
Presence of PHC teams with poor / regular grades 4128 74.1
No PHC team has poor / regular grades 1177 21.1

After evaluating the AAPC of acquired syphilis, categorized between upward, static or downward trend, the highest proportion arose in the category of the upward trend, with 87.4%.

Upon relating the AAPC of acquired syphilis with the PHC-related variables, as well as socioeconomic and demographic variables (Table 3), there was a significant association between the proportion of upward AAPC and the fully available rapid test (88.8%; p<0.001); partially available male condom (93.4%; p<0.001); partially available female condom (90.1%; p<0.001); partially available benzathine penicillin (88.6%; p<0.001); partial coverage of PHC teams (92.9%; p<0.001); partial application of penicillin in PHC (89.7%; p<0.001); higher proportion of women aged 10 to 17 years who had children (88.9%; p = 0.001); higher HDI (91.1%; p<0.001); higher proportion of teams classified as Poor/Regular in PHC (88.5%; p<0.001); and population size with more than 100,000 inhabitants (97.9%; p<0.001). There was no significant association between the AAPC and the Gini index and Proportion of persons aged 15 to 24 who do not study, do not work and are vulnerable.

Table 3. Comparison of the proportions of the AAPC trends with the variables related to the basic health service and socioeconomic factors.

AAPC
Category Growing trend Static or decreasing trend PR 95% CI p Value*
Rapid syphilis test in PHC
Fully Available 2603 (88.8%) 327 (11.2%) 1.04 1.02–1.06 <0.001
Partially available 2032 (85.3%) 350 (14.7%)
Male condom in PHC
Partially available 494 (93.4%) 35 (6.6%) 1.08 1.05–1.10 <0.001
Fully Available 4141 (86.6%) 642 (13.4%)
Female condom in PHC
Partially available 1631 (90.1%) 179 (9.9%) 1.05 1.03–1.07 <0.001
Fully Available 3004 (85.8%) 498 (14.2%)
Benzyl penicillin (penicillin G) in PHC
Partially available 3525 (88.6%) 452 (11.4%) 1.07 1.04–1.09 <0.001
Fully Available 1110 (83.1%) 225 (16.9%)
Coverage of PHC teams
Partial coverage 2475 (92.9%) 190 (7.1%) 1.14 1.11–1.16 <0.001
Fully covered 2159 (81.6%) 486 (18.4%)
Application of penicillin in PHC
Not all teams apply 2048 (89.7%) 234 (10.3%) 1.05 1.03–1.07 <0.001
All teams apply 2586 (85.4%) 442 (14.6%)
Gini index
>0.49 2391 (87.9%) 328 (12.1%) 1.01 1.99–1.03 0.226
Up to 0.49 2472 (86.9%) 374 (13.1%)
Proportion of women aged 10 to 17 who had children
>2.81 2463 (88.9%) 308 (11.1%) 1.03 1.01–1.06 0.001
Up to 2.81 2400 (85.9%) 394 (14.1%)
HDI
>0.665 2529 (91.1%) 246 (8.9%) 1.09 1.07–1.11 <0.001
Up to 0.665 2334 (83.7%) 456 (16.3%)
Proportion of persons aged 15 to 24 who do not study, do not work and are vulnerable
>32.89 2458 (88.4%) 323 (11.6%) 1.02 1.00–1.04 0.025
Up to 32.89 2405 (86.4%) 379 (13.6%)
Poor/regular grades teams in PHC
Presence of PHC teams with poor/regular grades 3655 (88.5%) 473 (11.5%) 1.07 1.04–1.10 <0.001
No PHC team has poor/regular grades 974 (82.8%) 203 (17.2%)
Population size
Up to 20000 inhabitants 3264 (83.3%) 655 (16.7%) 1.00 <0.001
20001–50000 inhabitants 1014 (97.2%) 29 (2.8%) 1.17 1.15–1.19
50001–100000 inhabitants 313 (96.3%) 12 (3.7%) 1.16 1.13–1.19
>100000 inhabitants 277 (97.9%) 6 (2.1%) 1.17 1.15–1.20

In the logistic regression analysis (Table 4), the following variables remained in the model: not all PHC teams apply penicillin (PRaj = 1.04; p = 0.002); higher proportion of PHC teams with poor/regular scores (PRaj = 1.05; p = 0.001); population size >100000 inhabitants (PRaj = 1.16; p<0.001); partially available female condom (PRaj = 1.03; p = 0.026).

Table 4. Independent AAPC-related factors of the growing trend.

Reference Predictor PR PRaj 95% CI p**
Application of penicillin in PHC
All PHC teams apply Not all teams apply 1.05 1.04 1.02–1.6 0.002
Poor/regular grades teams in PHC
No PHC team has poor/regular grades Presence of PHC teams with poor / regular grades 1.07 1.05 1.02–1.08 0.001
Population size*
20000 inhabitants >100000 inhabitants 1.17 1.16 1.08–2.24 <0.001
Female condom in PHC
Fully Available Partially available 1.05 1.03 1.00–1.05 0.038

* Dummy Variable

** Logistic Regression; Hosmer and Lemeshow = 0.702.

Discussion

This is the first research that sought to analyze predictors of the trend of acquired syphilis through PHC and sociodemographic indicators. There were significant associations of poor/regular quality of PHC teams, level of partial coverage of the basic health unit, fully available rapid syphilis test in PHC, partial availability of male condom and female condom, partial availability of benzathine penicillin and not all teams apply penicillin in PHC. Furthermore, there was a significant association of population size with more than 100,000 inhabitants, cities with higher HDI, cities with a higher proportion of women aged 10 to 17 years who had children and cities with the highest proportion of 15 to 24 years who do not study, do not work and are vulnerable in the population of this age group.

Syphilis is part of PHC-sensitive diseases. Thus, any modification in these services may directly influence its indicators [12,13]. In this study, a higher proportion of PHC teams with poor/regular scores and their significant association with upward syphilis AAPC was demonstrated, evidencing it as an important independent predictor, i.e., every PHC unit with poor/regular teams increases the upward trend of acquired syphilis by 18%.

A study developed in Australia by Nattabi et al. [14] demonstrated that the organizational factors of PHC, such as the clinic infrastructure, team profile and its quality can influence the tests and indicators of acquired syphilis. In their multivariate analysis, every improvement in the organizational indicator of the basic health service increased the syphilis indicator in remote populations by 5.1%. In this respect, indicators that measure quality in PHC are important predictors of acquired syphilis and teams classified as unsatisfactory may be contributing to the growth of the epidemic. Thus, the low quality of PHC may be favoring the growth of the acquired syphilis epidemic in Brazil, requiring improvements in its structure and health professionals to reverse the results presented in this study.

In Brazil, the number of families covered by PHC is calculated from territories, and their percentage of coverage between 2006 and 2016 was 45.3% and 64.0%, respectively [15]. Studies that evaluated the relationship between PHC coverage and syphilis show a significant association, such as the study by Nunes et al. [16], which evaluated the correlation between PHC coverage with congenital syphilis and in pregnant women, concluding that the cities with the lowest coverage were related to the higher rates of syphilis detection. Although this study did not address syphilis in the general population and did not test any predictor, cities with a larger number of families discovered by PHC probably influence the trends of acquired syphilis.

In relation to rapid syphilis tests in PHC, studies show them as a fundamental diagnostic triage tool to identify and contain the disease in places with little structure, especially in the identification of people without signs and symptoms, besides being fundamental for the algorithms of definition of cases for treatment [17,18].

In Brazil, the rapid test for syphilis is provided free of charge to the entire population [19], but its lack of supply is a reality and may be contributing to reduced number of diagnoses in PHC and, consequently, to the decreased number of people who should be under treatment. A study conducted in Brazil to verify the implementation of rapid tests in PHC showed that 37% did not have a rapid test in the health unit and 66.6% of the tests had expired [20].

Given the limitation of existing failures in syphilis triage in PHC, the available rapid tests can be rationed and directed only for use in pregnant women during prenatal care, which hinders its use in the general population. Testing the sexual partner and breaking the chain of transmission of the disease are an important challenge, as demonstrated in the study by Cavalcante, Pereira and Castro [21], whose number of partners untreated for syphilis reached 29.8%. Thus, the increase and improvement of management in the universal distribution of rapid tests in PHC can facilitate the triage of syphilis cases in the general population.

Regarding the treatment of syphilis, penicillin remains a highly effective medicine of choice for the individuals infected by Treponema [22,23]. The worldwide shortage of penicillin was the subject of the 6th WHO Assembly in Geneva [24], recognizing the shortage of the drug for many years in several countries of the world. In Brazil, it was not different [25]. The shortage of penicillin aggravated the syphilis crisis in the country and caused the Brazilian government to centralize the purchase and make direct distribution to the basic health care units, besides limiting its use only for cases of syphilis [26].

Even after centralized purchase and control in the use and distribution of penicillin, the shortage is still present in the PHC, suggesting that decentralization in drug management would be an important factor to control the epidemic [27,28]. In this sense, the impact of the lack of penicillin in PHC has also influenced the high trends of acquired syphilis in Brazil and the decentralization of its dispensing can improve the effectiveness in the rational use of the drug and reduce its lack in primary care services.

In addition to the availability of penicillin in PHC, there is a high proportion of cities that do not apply penicillin in PHC, favoring the growth of acquired syphilis. A study developed by Araújo et al. [27], which aimed to analyze structural aspects for the prevention of congenital syphilis, found that only 16.9% of the PHC units administered penicillin G, with probable fear of adverse effects of the drug and the lack of structure for its application. Ordinance N. 156, of January 19, 2006 of the Ministry of Health [29], established several criteria to act on adverse reactions in the use of penicillin in PHC, in addition to listing a minimum hospital structure for its use. This ordinance was revoked in 2011, removing these barriers, but it seems that the negative effects and fear of penicillin reactions by health professionals in PHC continues to negatively influence efforts to reduce the syphilis epidemic.

It is noteworthy that a systematic review study attested to the safety in the use of penicillin and did not find any evidence that justifies a hospital structure in PHC. In addition to stressing the safe use of the drug in pregnant women and in the general population, the study encourages that there should not be any political barrier to the use of penicillin in PHC [30]. Thus, the training of health teams to understand the safety in the use of penicillin in PHC can improve their application rates and, consequently, reduce an important barrier for the treatment of acquired syphilis at the site [7].

Another important action developed in PHC is the availability of male and female condoms. A study developed in India using multivariate models to identify coverage and the use of condoms for prevention of HIV and other STIs, in the audience of Men who have Sex with Men (MSM), sex workers and transgender people, demonstrated that the prevalence of reactive serology to syphilis significantly reduced in interventions with condoms, reducing from 8.8% to 1.1% the prevalence of syphilis [31].

In Brazil, a study that evaluated the risk practices of sex workers showed that 40.6% of the people studied did not receive condoms or received insufficient amounts. Although this study did not stratify the effect of social groups on condom use in relation to the upward trend of syphilis, it is likely that these effects will be repeated in the general population, especially if assessing the impact of female condoms on the prevention of syphilis.

The female condom is effective in the prevention of STIs and promotes female autonomy in sexual relations, especially when the partner denies the use of condoms [32]. The use of female condoms still has a low frequency when compared to male condoms, often due to low supply in health services and fear and unawareness of its use [33]. Thus, the promotion of the use of female condoms in PHC can reduce the higher upward trends of acquired syphilis in Brazil.

In relation to sociodemographic variables, studies show that small cities have greater coverage of PHC and, consequently, greater control of cases [34,35]. Naturally, smaller cities have a higher volume of case detection, due to their oscillation, but when evaluating the population size in upward trends, the larger cities are more important in determining the epidemic, which indicates a greater disorganization of the system against STIs. In relation to HDI, cities with better HDI have a greater difficulty in offering a significant number of prenatal consultations, increasing the probability of acquiring a STI [36].

As demonstrated in the course of this work, syphilis is a PHC-sensitive disease and its structure is fundamental for disease control. Most of the cities with better HDI are in the larger cities, but these do not offer a better equity in health care and syphilis control [37]. It is important to understand that, in relation to syphilis, PHC services are more attended by people with greater social vulnerability, suggesting that cities with better HDI have a greater disorganization in relation to syphilis control policies and that they should be better investigated regarding access to this policy.

Some limitations of this study are related to its nature with secondary data, such as the quality of notifications of acquired syphilis that became compulsory only in 2010, as well as the reliability of national censuses that assess a large volume of variables countrywide. Nonetheless, this study worked with consolidated data of acquired syphilis from 2011. Moreover, it is noticeable the improvement of the quality of the PMAQ records, whose collection is in its tenth year, which can avoid incomplete or inconsistent records by PCH teams. In addition, another limitation to consider is that Brazil is a huge country, with regional socio-demographic inequalities, which are related to the quality of primary care services. This could influence the relationships found in this study, even though these factors have been controlled.

In view of the above, important predictors of the upward trends of acquired syphilis were found in this study, such as the quality of the PHC service, penicillin applied in PHC, if the female condom is fully available and the influence of population size. Thus, measures aimed at improving access and quality of PHC, not only increasing the availability of penicillin, condoms and rapid tests at care places, but also bringing the training of health professionals in the care of STIs, become an indispensable tool, especially in large cities with a higher proportion of young people and young adults in vulnerability. New local studies need to be developed, mainly to understand whether the interventions in PHC suggested in this study can modify the high trends of acquired syphilis in the country.

Supporting information

S1 STROBE Checklist. Checklist of items that should be included in reports of cross-sectional studies.

(PDF)

S1 Table. Comparison of the proportions of the AAPC trends with the variables related to the basic health service and socioeconomic factors.

(xlsx).

(XLSX)

Data Availability

All files are available from the database https://doi.org/10.6084/m9.figshare.12844727.

Funding Statement

This research was funded by the Ministry of Health, and the Laboratório de Inovação Tecnológica em Saúde (LAIS/HUOL/UFRN) process number 732017, Project: "Syphilis No." The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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PLoS Negl Trop Dis. doi: 10.1371/journal.pntd.0009085.r001

Decision Letter 0

Jorg Heukelbach, Olivier Chosidow

20 Oct 2020

Dear Dr Marquiony Marques dos Santos

Thank you very much for submitting your manuscript "Weaknesses in primary health care favor the growth of acquired syphilis" for consideration at PLOS Neglected Tropical Diseases. As with all papers reviewed by the journal, your manuscript was reviewed by members of the editorial board and by several independent reviewers. In light of the reviews (below this email), we would like to invite the resubmission of a significantly-revised version that takes into account the reviewers' comments.

We cannot make any decision about publication until we have seen the revised manuscript and your response to the reviewers' comments. Your revised manuscript is also likely to be sent to reviewers for further evaluation.

When you are ready to resubmit, please upload the following:

[1] A letter containing a detailed list of your responses to the review comments and a description of the changes you have made in the manuscript. Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

[2] Two versions of the revised manuscript: one with either highlights or tracked changes denoting where the text has been changed; the other a clean version (uploaded as the manuscript file).

Editors' comments:

- Please present descriptive data in the abstract (number of cases, most important findings from descriptive analysis)

- The presentation of the formula for calculation of AAPC is not necessary - a citation of a reference will be sufficient.

Important additional instructions are given below your reviewer comments.

Please prepare and submit your revised manuscript within 60 days. If you anticipate any delay, please let us know the expected resubmission date by replying to this email. Please note that revised manuscripts received after the 60-day due date may require evaluation and peer review similar to newly submitted manuscripts.

Thank you again for your submission. We hope that our editorial process has been constructive so far, and we welcome your feedback at any time. Please don't hesitate to contact us if you have any questions or comments.

Sincerely,

Jorg Heukelbach

Guest Editor

PLOS Neglected Tropical Diseases

Olivier Chosidow

Deputy Editor

PLOS Neglected Tropical Diseases

***********************

Reviewer's Responses to Questions

Key Review Criteria Required for Acceptance?

As you describe the new analyses required for acceptance, please consider the following:

Methods

-Are the objectives of the study clearly articulated with a clear testable hypothesis stated?

-Is the study design appropriate to address the stated objectives?

-Is the population clearly described and appropriate for the hypothesis being tested?

-Is the sample size sufficient to ensure adequate power to address the hypothesis being tested?

-Were correct statistical analysis used to support conclusions?

-Are there concerns about ethical or regulatory requirements being met?

Reviewer #1: The methods used for the study were acceptable.

Reviewer #2: The objectives of the study are clearly articulated with a clear and testable hypothesis. The study design, as well as the sample (criteria and size) and its time frame are sufficient to meet the stated objectives and for the tested hypothesis.

The analyzes used support the considerations in the present work. The study used secondary, non-collectible ethical data involved.

Although not mandatory, a suggestion that can add even more value to the present study is based on the fact that these data are part of a national project for Rapid Response to Syphilis in Primary Health Care Networks, this project started in Brazil, approximately in 2018, and one of the objectives is to strengthen the fight against syphilis in priority municipalities in Brazil in primary health care, therefore, I suggest that the analyzes include data from 2019, since these actions of supporters in PHC teams can , or not, impact the findings presented until 2018.

--------------------

Results

-Does the analysis presented match the analysis plan?

-Are the results clearly and completely presented?

-Are the figures (Tables, Images) of sufficient quality for clarity?

Reviewer #1: The results are clearly presented; however Table 1, 2 and 3 need to be modified with shading or lines to separate the data presented for each variable. The current presentation makes it difficult for a readers eye to follow the row across.

Reviewer #2: The results are clear and consistent, despite the large number of variables and municipalities involved, the tables and charts are clear and are necessary for understanding the study.

--------------------

Conclusions

-Are the conclusions supported by the data presented?

-Are the limitations of analysis clearly described?

-Do the authors discuss how these data can be helpful to advance our understanding of the topic under study?

-Is public health relevance addressed?

Reviewer #1: The authors concludes are well described ans supported by the data analyzed.

The authors did a nice job describing how the data illuminate the public health crisis in Brazil and areas which could be improved to help reduce the number of acquired syphilis cases.

Reviewer #2: The conclusions presented are extremely important for coping with Syphilis Acquired in Brazil.

One of the limitations that the authors do not present is to consider the continental dimension of Brazil, which comprises many sociodemographic differences and inequality in health care coverage in the country, the latter being an important factor in discussing these results.

This study type of study is very important for Public Health, as it relates the service at PHC and the trend of acquired syphilis cases, since in Brazil, it is these teams in primary health care that are at the forefront of coping to that epidemic.

--------------------

Editorial and Data Presentation Modifications?

Use this section for editorial suggestions as well as relatively minor modifications of existing data that would enhance clarity. If the only modifications needed are minor and/or editorial, you may wish to recommend “Minor Revision” or “Accept”.

Reviewer #1: A few minor revisions are required:

1. The author needs to define HDI when it first appear in the document.

2. The Tables need to be reformatted to allow for easier interpretation by the readers. Addition of shading or lines should improve this issue.

3. If the data are available, it's recommenced that the authors include a table with specifics about the cohort reviewed (e.g. sex, mean age, sexual preference, stage of diagnosed syphilis, etc)

3. On lines 75-77, the authors need to clarify what "group" is they are considering neglected.

Reviewer #2: The suggestion would be to review the data including the 2019 data in the analyzes, as already indicated in the comments on the method.

--------------------

Summary and General Comments

Use this section to provide overall comments, discuss strengths/weaknesses of the study, novelty, significance, general execution and scholarship. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. If requesting major revision, please articulate the new experiments that are needed.

Reviewer #1: The manuscript by Marques dos Santos, et al. supports the idea that modification to Brazil's primary health care systems could help reduces the number of acquire syphilis cases. In general the manuscript is well written and with the minor revisions, this manuscript will help other regions globally to investigate similar factors such as primary health care and sociodemographic structures, and with attention could significantly influence a reduction in syphilis cases.

Reviewer #2: The article discusses an acquired syphilis that has its rates increasing worldwide. This article presents the perspective of the tendency of Syphilis Acquired with Primary Health Care, this look will contribute a lot to the understanding of the increase of an easily treatable and dysagnotic disease, but despite that, its rates continue to increase.

--------------------

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Reviewer #1: No

Reviewer #2: No

Figure Files:

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PLoS Negl Trop Dis. doi: 10.1371/journal.pntd.0009085.r003

Decision Letter 1

Jorg Heukelbach, Olivier Chosidow

22 Dec 2020

Dear Colleague

To:Marquiony Marques dos Santos

We are pleased to inform you that your manuscript 'Weaknesses in primary health care favor the growth of acquired syphilis' has been provisionally accepted for publication in PLOS Neglected Tropical Diseases.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. A member of our team will be in touch with a set of requests.

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

Should you, your institution's press office or the journal office choose to press release your paper, you will automatically be opted out of early publication. We ask that you notify us now if you or your institution is planning to press release the article. All press must be co-ordinated with PLOS.

Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Neglected Tropical Diseases.

Best regards,

Olivier Chosidow

Deputy Editor

PLOS Neglected Tropical Diseases

Olivier Chosidow

Deputy Editor

PLOS Neglected Tropical Diseases

***********************************************************

PLoS Negl Trop Dis. doi: 10.1371/journal.pntd.0009085.r004

Acceptance letter

Jorg Heukelbach, Olivier Chosidow

29 Jan 2021

Dear Dr. Santos,

We are delighted to inform you that your manuscript, "Weaknesses in primary health care favor the growth of acquired syphilis," has been formally accepted for publication in PLOS Neglected Tropical Diseases.

We have now passed your article onto the PLOS Production Department who will complete the rest of the publication process. All authors will receive a confirmation email upon publication.

The corresponding author will soon be receiving a typeset proof for review, to ensure errors have not been introduced during production. Please review the PDF proof of your manuscript carefully, as this is the last chance to correct any scientific or type-setting errors. Please note that major changes, or those which affect the scientific understanding of the work, will likely cause delays to the publication date of your manuscript. Note: Proofs for Front Matter articles (Editorial, Viewpoint, Symposium, Review, etc...) are generated on a different schedule and may not be made available as quickly.

Soon after your final files are uploaded, the early version of your manuscript will be published online unless you opted out of this process. The date of the early version will be your article's publication date. The final article will be published to the same URL, and all versions of the paper will be accessible to readers.

Thank you again for supporting open-access publishing; we are looking forward to publishing your work in PLOS Neglected Tropical Diseases.

Best regards,

Shaden Kamhawi

co-Editor-in-Chief

PLOS Neglected Tropical Diseases

Paul Brindley

co-Editor-in-Chief

PLOS Neglected Tropical Diseases

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 STROBE Checklist. Checklist of items that should be included in reports of cross-sectional studies.

    (PDF)

    S1 Table. Comparison of the proportions of the AAPC trends with the variables related to the basic health service and socioeconomic factors.

    (xlsx).

    (XLSX)

    Attachment

    Submitted filename: Letter_PlosNegletec_2.docx

    Data Availability Statement

    All files are available from the database https://doi.org/10.6084/m9.figshare.12844727.


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