Nursing students’ knowledge and attitudes toward human papillomavirus vaccination and infection

ABSTRACT

Human papillomavirus is responsible for 70% cervical cancers worldwide. The study assessed nursing students’ knowledge and attitudes toward human papillomavirus vaccination and infection. A descriptive design was employed among nursing college students between 18 and 25 were selected as a purposive sample for the study. The study was conducted at the Menoufia University-affiliated Faculty of Nursing. A structured online questionnaire including sociodemographic data, level of knowledge about human papillomavirus infection and vaccination, and nursing students’ attitudes toward HPV vaccination. The total knowledge of HPV infection and vaccination was low, 36.6% and 45.1%, respectively. The total attitude toward HPV vaccination was negative mean 27 ± 3.8. The total attitude toward HPV infection was negative mean 25 ± 1.1. Students’ knowledge about HPV infection and vaccination was positively correlated with attitude. None of nursing students not received HPV vaccination. Provide nursing university students with educational packages to improve their attitudes toward the future of the HPV vaccine and to increase their understanding of HPV.

Introduction

After ovarian and endometrial cancers, cervical cancer ranks third globally among genital tract malignancies, and it is a serious health concern. In terms of mortality, cervical cancer ranks second globally among genital tract malignancies, after ovarian tumors.¹ For Egyptian women aged 15 to 45, cervical cancer ranks as the tenth most common malignant illness.²

Cervical cancer is the 12th most common cause of death for Egyptian women, according to estimates of mortality costs in Egypt.^3,4 One of the most substantial diagnosed reasons for cervical cancer is the human papillomavirus.^5,6 As types 16, 18, 31, 33, and so on, early proteins 6 and 7 (E6, E7) of high-risk genotypes function as carcinogenic proteins.⁷ The tumor-suppressor protein P53 is broken down by the E6 protein, which shortens its half-life from many hours to less than 20 min.^8,9

To save lifestyles from threatening cervical cancer in Egypt and the local community, it is crucial to recognize the occurrence of excessive-hazard or low-hazard human papilloma virus genotypes. Vaccines for HPV types 16, 18, 11, and 6, in addition to related cervical intraepithelial neoplasia and adenocarcinoma, are endorsed. Regular screening for early intraepithelial lesions and invasive cervical cancer can assist. HPV vaccines are also for elderly women, elderly boys, and people with HIV or undergoing chemotherapy or radiotherapy.^10,11

Nursing students are crucial in educating communities about HPV contamination and vaccination, shaping public perceptions and reputation. However, research shows that healthcare providers’ information gaps and poor attitudes toward the direction of HPV vaccination can preclude effective immunization campaigns, especially in rural and underserved areas.^8,9 Nursing students’ ignorance and attitudes toward HPV contamination and prevention can be attributed to a variety of factors. These factors include inaccurate information, cultural and societal standards, and a lack of promotion of HPV-related resources. These impediments must be addressed to prepare nursing college students.

Human papillomavirus (HPV) is a primary public health problem, as it is not an unusual sexually transmitted contamination and is related to quite a few cancers, along with cervical cancer.^12,13 Vaccination has been proven to be distinctly powerful in preventing HPV-associated sicknesses; however, information gaps and negative attitudes about the vaccine remain standard, specifically among healthcare professionals, together with nursing college students.^14,15 A study assessing nursing students’ knowledge and attitudes about HPV and vaccination found that despite a high level of knowledge about HPV, misconceptions about its transmission and prevention persisted.^16,17 Furthermore, 42% of participants were accurately aware of the vaccine’s shielding effects against certain cancers, and many expressed hesitancies in recommending it because they did not fully understand its safety profile.^17,18 Another study conducted in a medical nursing place found that educational interventions significantly improved people’s knowledge and attitudes concerning HPV vaccination. Pre-intervention, the best 35% of nursing students identified the vaccine’s position in reducing cervical cancer’s prevalence; however, this improved to 78% post-intervention.^19,20 Similarly, the percentage of students willing to advocate for the vaccine rose demonstrating the capacity effect of focused training.²¹ Differences in knowledge and vaccination uptake are evident globally, with cultural, social, and educational factors stimulating variations. For instance, a multi-institutional study evaluating nursing students in high-income and coffee-profit settings reported that 64% of college students in high-income nations had comprehensive expertise about HPV and vaccination.^22,23 This study conducted to assess nursing students’ knowledge and attitudes toward vaccination and human papillomavirus infection.

Research questions

1. What is the nursing students’ knowledge level about human papillomavirus infection and vaccination?

2. What is the attitude of nursing students toward human papillomavirus infection and vaccination?

3. Is there correlation between nursing students’ knowledge and their attitudes?

Methods

Research design

This study utilized a descriptive research design.

Research settings and Sample

The study was conducted at the Menoufia University-affiliated College of Nursing. Undergraduate nursing students were recruited using a convenience sampling method for ease and practicality, with 530 students aged 18–25 y participating in the survey.

Calculation of sample size

To calculate the required sample size, the researchers applied Yamane’s algorithm. n = N/(1 + N (e) 2).

The letter n stands for the sample size being shown.

The total number of research participants is denoted by N.

In the calculation, is equivalent to a 5% margin of error.

A total sample of 530 nursing students participated.

The criteria for inclusion and exclusion consist of undergraduate nursing students who were chosen for the study (enrolled from the first to the fourth year of the nursing program). Postgraduate master’s or doctoral students, people with a history of severe allergies or yeast allergies, people who have had a life-threatening allergic reaction to the HPV vaccine or any of its ingredients, patients with moderate to severe illness, and people who are unwilling to participate in the study were all excluded.

Data collection tools

To get the necessary data, three main tools were employed:

Tool one: A structured online questionnaire. There are three components to it:

I: It includes the sociodemographic data: Age, sex, education, place of residence, marriage status, smoking status, and economic standing.

II: Nursing students’ knowledge about HPV infection and vaccination. It includes description, risk factors, typical symptoms, consequences, ways to avoid early discovery, usual treatment, the concept of HPV vaccination, its significance, the population it is intended for, the recommended age for HPV vaccination, the kinds of HPV vaccines that are available, and dosages of the vaccines, doses of the HPV vaccine typically required, methods of administration of the HPV vaccine, and contraindications for giving the HPV vaccine.

Knowledge scoring system

Every question on the knowledge level scored 2 for a right response, 1 for a wrong one, and 0 for not knowing. The sum of the scores for the “known items” was used to get the overall knowledge score. Percentages were calculated from the scores. The following is the total knowledge score: good scores are greater than 75%, moderate scores are between 75% and 50%, and low scores are less than 50%.^4,12

III: The attitudes of nursing students toward HPV infection and vaccination developed by researchers based on a literature review.^4,12

Scoring system

This questionnaire included items based on a Likert scale that went from strongly disagree (1) to strongly agree (5). Then, data were split into “negative (<28)” and “positive (≥28), based on author instructions.²²

Validity and reliability

The validity of the instruments was certified by five specialists, including two professors from the Faculty of Medicine’s Obstetrics and Gynecology department and three professors from the Faculty of Nursing’s Maternal and Newborn Health Nursing department. They evaluated the instruments’ internal validity and content accuracy. They were also told to assess the items’ content validity, or how comprehensive and understandable they were. The researchers used test-retest reliability to assess the internal consistency of the instruments. In comparable circumstances, the same personnel and equipment were used to finish the assignment. To evaluate the stability of the results, certain tests were examined twice, separated by 3 weeks. Cronbach’s α ratings for part 2 and part 3 were 0.90 and 0.95, respectively, indicating that all the tools were internally reliable.

Ethical considerations

The Faculty of Nursing at Menoufia University’s Research and Ethics Committee gave its clearance to carry out the study (Research No., 1038). They were informed that participation was optional, and each student could leave whenever she wanted. Students could decline participation without restrictions and were free to inquire about any specific information regarding the research.

Pilot study

About 10% of the sample (53 students) participated in an exploratory study to evaluate the suitability of the instruments, the research’s viability, and the amount of time needed for data collection. None of the students who participated in the pilot trial were included in the main study to guarantee consistent results and make the necessary adjustments.

Data collection

The researchers gave a brief introduction and described the goal of the study. The survey was created online using Question Pro and disseminated to the study sample via WhatsApp groups and e-mails from the Faculty of Nursing’s student affairs department. Tool one, part II and III were used to evaluate each student’s attitude and degree of knowledge. The participants spent roughly 15 min filling out the questionnaire. This procedure was followed until the required quantity was obtained. Recruited participants between March and May 2024.

Analysis of statistics

An IBM personal computer running the Statistical Package of Social Science (SPSS) version 25 (SPSS, Inc., Chicago, Illinois, USA) was used to gather, tabulate, and statistically analyze the data. The following statistics were used: In descriptive statistics, qualitative data were displayed as numbers and percentages, while quantitative data were displayed as means and standard deviations (SD). A test for determining the relationship between quantitative variables is the Pearson correlation (r). A P value greater than 0.05 was deemed statistically insignificant. Statistical significance was defined as a P value of less than 0.05.

Results

More than half of the analyzed students (59.5%) were aged 21 or older, as shown in Table 1. More than two-thirds (73.4%) were female. In terms of smoking status, the majority (93.6%) were nonsmokers. More than two-thirds of residents (72.3%) resided in rural areas. Most of them were single (91.3%). Less than half of them had a median income (43.2%). Although over half had heard about the vaccination (57.7%), none had received it. Table 1

Figure 1.

Academic year of studied participants (n = 530).

Less than half of the studied students (40.6%) were in their second academic year, as illustrated in Figure 1.

Table 1.

Characteristics of the participants in the study (n = 530).

Demographics	No.	%
Age
18–20 y	214	40.5
≥21 y	315	59.5
Sex
Male	141	26.6
Female	389	73.4
Smoking status
Smoker	34	6.4
Non-smoker	496	93.6
Residence
Urban	147	27.7
Rural	383	72.3
Marital status
Single	484	91.3
Married	46	8.7
Economic status
Low	203	38.3
Middle	229	43.2
High	98	18.5
HPV vaccination status
Not vaccinated	530	100.0
Knowledge of the HPV vaccination
Heard about the vaccine	306	57.7
I had never heard of the vaccine before.	224	42.3

The total frequency of correct answer in term of knowledge of HPV infection was low 36.6%. In terms of definition of HPV infection, 38.5% reported a correct answer. Less than half knew risk factors, common symptoms, and complications of HPV infection (37.9%, 38.2%, 38.3%), respectively.

Less than half do not knew early detection of HPV infection 38.0%, and most effective method for preventing HPV infection 38.3%. Table 2

Table 2.

Level of knowledge of HPV infection (n = 530).

Items	Correct answer		Incorrect answer		Don’t know/have any opinion
	No.	%	No.	%	No.	%
HPV is a sexually transmitted disease/infection.	204	38.5	147	27.7	179	33.8
Having HPV puts one at risk for cervical cancer	107	20.2	201	37.9	222	41.9
HPV is an infection that only affects women	233	44.0	133	25.1	164	30.9
Risk factors for acquiring HPV infection.	201	37.9	116	21.9	213	40.2
Common symptoms of HPV infection.	205	38.2	131	24.7	194	36.6
Complications of HPV infection.	203	38.3	125	23.6	202	38.1
The most effective method for preventing HPV infection.	202	38.1	125	23.6	203	38.3
Early detection of HPV infection.	176	32.2	158	29.8	196	38.0
Necessary preparation before an HPV test.	70	13.2	228	43.0	232	43.8
Common treatment option for visible genital warts caused by HPV.	137	25.8	211	39.8	182	34.3
A key strategy in raising awareness and preventing HPV infection.	405	76.4	24	4.5	101	19.1

The total frequency of correct answer in term of knowledge of HPV vaccination was low 45.1%. The majority of students knew the correct definitions of HPV vaccination (71.5%). Less than half of students answered correct answer in terms of HPV vaccine component (46.4%). Almost two-third of students answered the correct answer for items importance of HPV vaccination, contraindications and vaccine protect against HPV-related diseases. In another hand, almost half of students do not knew the answered for items targeted population and Doses of the HPV vaccine. Table 3

Table 3.

Level of knowledge of HPV vaccination (n = 530).

Items	Correct answer		Incorrect answer		Don’t know/no opinion
	No.	%	No.	%	No.	%
Definition of HPV vaccination.	379	71.5	57	10.8	94	17.7
Component of the HPV vaccine.	246	46.4	111	20.9	173	32.6
Importance of HPV vaccination.	353	66.6	81	15.3	96	18.1
Targeted population for HPV vaccination.	68	12.8	201	37.9	261	49.2
Recommended age for HPV vaccination.	146	27.5	242	45.7	142	26.8
Types of available HPV vaccines.	98	18.5	98	18.5	334	63.0
Doses of the HPV vaccine typically required.	169	31.9	104	19.6	257	48.5
Method of administration of the HPV vaccine.	229	43.2	92	17.4	209	39.4
Contraindications for giving the HPV vaccine.	350	66.0	43	8.1	137	25.8
To what extent HPV vaccine protect against HPV-related diseases.	341	64.3	42	7.9	147	27.7
Typical adverse effects of HPV vaccine.	251	47.4	107	20.2	172	32.5

Table 4 demonstrates that a sizable portion of students, 79.8%, said they would be open to talking about sexually transmitted diseases like HPV. Also, 79% agreed that Pap smears are an essential diagnostic tool for early HPV detection and cervical cancer. According to 75.1% of students, Pap smears regularly reduce the risk of dying from cervical cancer. It was agreed upon by 78.1% that screening for cervical cancer should begin at age 21 for all married women. The total attitude toward HPV infection was negative mean 25 ± 1.1.

Table 4.

Attitude toward HPV infection (n = 530).

Items	Strongly agree		Agree		Neutral		Disagree		Strongly disagree
	No.	%	No.	%	No.	%	No.	%	No.	%
I want to discuss sexually transmitted infections, such as HPV.	227	42.8	196	37.0	74	14.0	11	2.1	22	4.2
The Pap smear is a crucial diagnostic method for cervical cancer and HPV early detection.	184	34.7	235	44.3	96	18.1	11	2.1	4	0.8
Pap smears consistently lower the risk of cervical cancer-related death.	188	35.5	210	39.6	113	21.3	14	2.6	5	0.9
Every married woman should get screened for cervical cancer starting at age 21 y. The screening is unrelated to complaints of symptoms or issues.	229	43.2	185	34.9	94	17.7	14	2.6	8	1.5
Fear of the test’s outcome.	197	37.2	199	37.5	101	19.1	25	4.7	8	1.5

Table 5 shows that 381/530 (71.9%) of the students, or more than two-thirds of them, believed that HPV vaccination is very safe and effective. Three hundred and thirty-five out of 530 students, or more than two-thirds, agreed that the HPV vaccination will result in fewer Pap smear tests being conducted. Moreover, 51.7% of the responders affirmed that their yearly Pap smear examinations are not as good as HPV vaccinations. About 61.7% of respondents, or more than two-thirds, agreed that the HPV vaccine reduces cervical cancer. Also, 70% of the students believed that HPV vaccination reduces the frequency of Pap smear tests. The total attitude toward HPV vaccination was negative mean 27 ± 3.8.

Table 5.

Attitude toward HPV vaccination (n = 530).

Items	Strongly agree		Agree		Neutral		Disagree		Strongly disagree
	No.	%	No.	%	No.	%	No.	%	No.	%
Vaccination against HPV is extremely effective and secure.	165	31.1	216	40.8	128	24.2	13	2.5	8	1.5
Fewer Pap smear tests will be performed because of HPV vaccination.	133	25.1	202	38.1	149	28.1	39	7.4	7	1.3
Having HPV vaccination is preferable to yearly Pap smear tests.	112	21.1	162	30.6	162	30.6	78	14.7	16	3.0
HPV vaccine prevents cervical cancer.	114	21.5	213	40.2	163	30.8	32	6.0	8	1.5
Immunization against HPV lowers the Pap smear frequency.	128	24.2	243	45.8	124	23.4	28	5.3	7	1.3
Ministry of Health’s vaccination schedule in Egypt should include the HPV vaccination.	200	37.7	227	42.8	87	16.4	11	2.1	5	0.9
The vaccination should be funded by the Ministry of Health.	254	47.9	180	34.0	87	16.4	5	.9	4	0.8
Adolescents should be strongly encouraged to receive HPV vaccinations.	200	37.7	191	36.0	112	21.1	22	4.2	5	0.9
I want to get vaccinated against HPV	164	30.9	189	35.7	141	26.6	22	4.2	14	2.6

This score was considerably higher for students aged ≥21 y, in the last years of their academic year degree, females, living in rural areas, single, of high economic status, and aware of the vaccine’s existence. The mean attitude score was 28.28 ± 8.50, which was substantially higher for students aged 18–20 y, in the early years of their academic year, males, who had a low economic status, and who were unaware of the vaccine’s existence. Table 6

Table 6.

Students’ knowledge and attitude scores stratified by their characteristics.

	Knowledge Score (Mean ± SD)	p	Attitude Score (Mean ± SD)	p
All participants	23.30 ± 10.10		28.28 ± 8.50
Age
18–20 y	19.44 ± 11.92	<.001	30.47 ± 9.43	<.001
≥21 y	25.93 ± 7.60		26.78 ± 7.45
Sex
Male	12.07 ± 9.10	<.001	32.39 ± 9.66	<.001
Female	27.86 ± 6.15		26.61 ± 7.37
Smoking status
Smoker	22.88 ± 11.11	.801	27.00 ± 7.76	.364
Non-smoker	23.33 ± 10.04		28.36 ± 8.55
Residence
Urban	21.00 ± 10.94	.001*	28.18 ± 8.48	.870
Rural	24.18 ± 9.63		28.31 ± 8.51
Marital status
Single	23.60 ± 9.95	.027*	28.30 ± 8.41	.815
Married	20.15 ± 11.20		28.00 ± 9.49
Academic year
First year	5.08 ± 4.78	<.001	34.21 ± 10.83	<.001
Second year	21.04 ± 3.19		29.80 ± 7.62
Third year	27.21 ± 2.86		26.63 ± 6.83
Fourth year	30.92 ± 3.08		25.64 ± 6.84
Economic status
Low	13.22 ± 9.05	<.001	31.85 ± 9.64	<.001
Middle	28.18 ± 2.98		26.22 ± 7.13
High	32.78 ± 2.30		25.67 ± 6.098
Awareness of HPV vaccine
Heard about the vaccine before	29.64 ± 3.55	<.001	26.09 ± 6.74	<.001
Never heard about the vaccine	14.64 ± 9.71		31.26 ± 9.68

*(p < .05).

Students’ knowledge about HPV infection and vaccination was positively correlated with attitude, as Table 7 demonstrates.

Table 7.

Correlation between knowledge and attitude score among nursing students.

	Knowledge
	R	P- value
Attitude	0.358**	0.000

Discussion

The human papillomavirus is one of the most common STIs, infecting about 5.5 million people. The study assessed nursing students’ knowledge and attitudes toward human papillomavirus vaccination and infection. A preliminary knowledge assessment indicated substantial gaps in the sampled students’ understanding of HPV-related concepts. The findings of the present study revealed that nursing students possessed low knowledge regarding HPV infection and vaccination. This limited awareness could be attributed to their overall lack of exposure to accurate information about the human papillomavirus, as evidenced by the fact that none of the participants had received the HPV vaccine.²⁴ Furthermore, this knowledge deficit highlights a critical need to integrate comprehensive HPV education into nursing curricula. Enhancing students’ understanding of HPV transmission, prevention, and vaccination could not only improve their personal health behaviors but also strengthen their ability to educate future patients effectively.²⁵ Targeted interventions, such as workshops, seminars, or evidence-based training modules, may therefore play an essential role in bridging these gaps and promoting vaccine advocacy within the healthcare community²⁶

A recent study validated the findings of this study by revealing that nursing college students knew little to nothing about HPV and the HPV vaccine.^15,25 According to national study, slightly more than half of the nursing students in the study had average awareness of vaccinations, and around two-thirds had an average understanding of the human papillomavirus and Pap smear.²¹ Also, studies found that when it came to attitudes toward HPV vaccination and the intention to get vaccinated among female university students in Jordanian health schools, nursing students had the lowest level of HPV knowledge (29,30). Other studies found that people who needed more information on HPV infection and preventive measures were less informed than those who had received information from doctors about these topics.^13–29

The finding that none of the participating nursing students had received the HPV vaccine is particularly concerning, given their role as future healthcare providers. Several factors may contribute to this 0% vaccination rate, including a lack of awareness or knowledge about HPV and its associated health risks, cultural or social beliefs regarding vaccination, perceived low personal risk, and limited access to the vaccine.³⁰ This absence of vaccination not only places the students themselves at risk of HPV-related infections but also has broader implications for public health. As future nurses, their attitudes and personal health practices can influence patient education and advocacy. If nursing students remain unvaccinated and uninformed, they may be less likely to recommend the HPV vaccine confidently to their patients, potentially perpetuating low vaccination coverage within the community. This highlights the urgent need for targeted educational interventions and vaccination campaigns within nursing programs to ensure that future healthcare providers are both knowledgeable and protected, ultimately enhancing their ability to promote HPV prevention effectively.²⁷

There was broad consensus regarding the HPV vaccine’s importance in preventing and reducing cervical cancer, possibly even more so than pap smears. In addition, there is an urgent need to promote and facilitate vaccine administration. According to Cinar et al., just 7% of students were aware of the HPV vaccine, while over 33% of participating college students claimed to have received it.¹¹ According to the same findings, three-quarters of people would be willing to take an HPV vaccination if given freely, but only roughly one-fifth would be willing to pay for it.^15,28

In this study, male nurses demonstrated a generally positive attitude toward the HPV vaccine. This finding may be attributed to the perception that women are at greater risk of HPV-related complications and therefore require additional protection. Moreover, there is a common belief that HPV infection in women could potentially affect pregnancy outcomes or be transmitted to the unborn child.³¹

The results showed a strong association between nursing students’ knowledge and attitudes about HPV and their socio-demographic characteristics. Furthermore, among the nursing students under study, there was a noteworthy association between their attitudes and knowledge about immunization and human papillomavirus infection. Students over 21 y old, residing in rural areas, and aware of the existence of the vaccination had the highest average knowledge score during the previous academic year. The female nursing students’ growth and development stage between adolescence and adulthood may have contributed to this outcome since they developed an interest in women’s health awareness.

Additionally, study revealed that medical students and older participants had considerably higher intentions to get vaccinated against HPV.²⁸ Another study found a strong relationship between the academic year of nursing students and their attitudes and knowledge about HPV.³² In addition to the previous findings, a statistically significant relationship was observed between nursing students’ overall knowledge and their overall attitudes, which aligns with our results.²¹ In contrast to our findings, they discovered no statistically significant relationship between students’ total knowledge and attitudes. Since all medical students are included in the study, the researchers believe this could be because of the various study group.^33,34 By integrating comprehensive HPV education into nursing programs, students can develop a deeper understanding of the virus, its transmission, and the importance of vaccination in disease prevention.^35,36 This knowledge will not only empower them to make informed personal health decisions but also enable them to effectively educate and advocate for vaccination among their future patients. Ultimately, strengthening nursing students’ knowledge and attitudes toward HPV can contribute significantly to public health efforts aimed at reducing HPV-related diseases.

Conclusion

The study found that nursing students had low levels of knowledge about HPV infection (36.6%) and HPV vaccination (45.1%). Their attitudes toward both HPV infection (mean = 25 ± 1.1) and HPV vaccination (mean = 27 ± 3.8) were generally negative. Although students’ knowledge was positively correlated with their attitudes, it is particularly concerning that none of the nursing students had received the HPV vaccine. This finding underscores a critical gap between knowledge and preventive practice, emphasizing the urgent need for targeted educational initiatives and institutional efforts to promote HPV vaccination among future healthcare professionals.

Biography

Faten Mabrouk Nouh Dr Nouh is an Assistant Professor of Pediatric Nursing at the Faculty of Nursing, Al-Zaytoonah University of Jordan. She received her Ph.D. in Pediatric Nursing from Menoufia University, Egypt, in 2022, with a dissertation on “Effect of Developing Nursing Practice Guidelines on Comfort Behavior in Intubated Pediatric Patients.” Dr Nouh has extensive academic and clinical teaching experience, having served as a lecturer, assistant lecturer, and clinical instructor at Menoufia University, Egypt, before joining Al-Zaytoonah University in 2024. Her research interests focus on pediatric nursing, child health, and innovative approaches in nursing education, with particular emphasis on critical and emergency care and comfort measures for children. She has contributed to multiple publications in peer-reviewed journals, supervised postgraduate theses, and participated in numerous conferences, workshops, and training programs. Dr Nouh is a member of several professional and academic committees, including quality assurance and extracurricular activities committees, and actively engages in community service initiatives.

Funding Statement

The research was funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number [PNURSP2025R293], Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.

Disclosure statement

No potential conflict of interest was reported by the author(s).