The trend of paediatric cases during the first year of the COVID-19 pandemic in North Sumatra, Indonesia

Highlights

• •The incidence of positive SARS-CoV-2 cases was 1.9% among the children tested in North Sumatra, Indonesia.
• •The predominant age group of children with COVID-19 was 6–11 years.
• •Public holidays and the introduction of a new variant contributed to an increase in cases.
• •Children accounted for a much higher proportion of general SARS-CoV-2 infection.

Abstract

Objective

The aim of the study was to describe the epidemiology of coronavirus disease 2019 (COVID-19) cases in children in North Sumatra Province during the period June 2020 to July 2021.

Methods

This study included samples from children in North Sumatra Province aged 0–17 years, suspected to have COVID-19. A case of COVID-19 was confirmed by RT-PCR in the Microbiology Laboratory, Faculty of Medicine, Universitas Sumatera Utara, Indonesia. Data were collected from June 2020 to July 2021. Demographic data including age, sex, and date of diagnosis were collected. A descriptive statistical analysis was performed, and ratios or percentages were compared.

Results

A total of 117 650 people were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and 2222 (1.9%) children were positive. The age group 6-11 years had the highest proportion of cases with 679/2222 cases (30.6%). Overall, the number of positive COVID-19 cases peaked in July 2021, with 650 cases and a positivity rate of 3.0%. In 2020, the greatest proportion of cases occurred in the age group of 12–14 years; however, this changed to the age group 6-11 years in 2021.

Conclusions

COVID-19 was detected in all paediatric age groups in North Sumatra during the study period. Incidence peaks occurred due to mass gatherings, public holidays, and the introduction of a new variant in Indonesia. Children accounted for a much higher proportion of SARS-CoV-2 infection compared to those reported in other studies and could have played a role as the source of transmission in society.

1. Introduction

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread widely around the world, resulting in a global public health problem. On March 11, 2020, The World Health Organization declared COVID-19 to be a pandemic, and as of April 2020, a total of 2 314 621 confirmed cases and 157 847 fatal cases had been reported [1].

The first case of COVID-19 in Indonesia was reported on March 2, 2020, and it spread quickly to all provinces, resulting in a significant expansion of cases and deaths. Indonesia became one of the top 20 countries with the highest number of COVID-19 cases [2].

This study was performed to explore the trend of COVID-19 cases among children in North Sumatra Province, Indonesia, and its association with the government-implemented measures to control the spread of COVID-19.

2. Methods

This was a retrospective study evaluating the prevalence of COVID-19 among children in North Sumatra Province, Indonesia. Individuals residing in North Sumatra Province, Indonesia, who were aged <18 years and had symptoms of COVID-19 or had been in close contact with a COVID-19 confirmed patient between June 1, 2020 and July 31, 2021, were screened for SARS-CoV-2 infection by real-time reverse transcription PCR (RT-PCR) using nasopharyngeal–oropharyngeal samples. All analyses were performed in the Microbiology Laboratory, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia. Demographic data including age, sex, and date of diagnosis were collected. A descriptive statistical analysis was performed, and ratios or percentages were compared. The software program IBM SPSS Statistics version 26.0 (IBM Corp., Armonk, NY, USA) was used for the statistical analysis. The study was approved by the Ethics Committee of the Faculty of Medicine, Universitas Sumatera Utara (Ref. No. 568/KEP/USU).

3. Results

A total of 117 650 individuals were tested for SARS-CoV-2 infection by RT-PCR during the study period. Of these, 13 136 were children younger than 18 years of age. The overall positivity rates were 29.2% (34 452), and 2222 children (.6.4%) tested positive. Overall, the proportion of male and female infected with COVID-19 were 51.4% and 48.6%, respectively. There was no significant difference in sex distribution of the cases between the period of June-December 2020 and January-July 2021 (P > 0.05; Table 1). Among the 2222 positive children, the highest proportion were in the age group 6–11 years (30.6%), followed by 15–17 years (25.4%), 12–14 years (23.9%), and 0–5 years (20.1%). In 2020, the greatest pproportion of cases occurred in the age group 12-14 years (30.4%); however, in 2021, this changed to the age group 6-11 years (32.6%) (P < 0.001; Table 1, Figure 1)..

Figure 1.

Age profile of confirmed paediatric COVID-19 cases.

Table 1.

Characteristics of paediatric patients with COVID-19.

Variables	Overall	2020	2021	P-value
Number testeda	117 650	40 943	76 707
Total number positive	2222	520	1702
Sex, n (%)				0.900
Male	1142 (51.4%)	266 (51.2%)	876 (51.5%)
Female	1080 (48.6%)	254 (48.8%)	826 (48.5%)
Age, n (%)				<0.001
0–5 years	447 (20.1%)	117 (22.5%)	330 (19.4%)
6–11 years	679 (30.6%)	123 (23.6%)	556 (32.6%)
12–14 years	532 (23.9%)	158 (30.4%)	374 (22.0%)
15–17 years	564 (25.4%)	122 (23.5%)	442 (26.0%)

^aJune 2020 to July 2021.

During the 14-month observation period, the number of children tested increased 4.5 times from 4716 tests in June 2020 to 21 633 tests in July 2021 (Figure 2). The monthly positivity rate ranged from 0.6% to 3.2%. There were several interventions put in place by the provincial government to contain the spread of COVID-19, including restrictions on international and domestic travel, school closure, workplace closure, cancellation of public events, restriction on gatherings, restriction on public transport, and stay-at-home recommendation [3]. The control measures were introduced based on evaluations of the numbers of positive cases and in preparation for public holidays (i.e., Eid al-Fitr, Christmas holidays). Regarding the prevention of infection in children, face-to-face learning in schools was changed to virtual learning from March 2020 to December 2021, before it was re-started in January 2022. However the same measure only lasted until June 2020 for boarding schools. Moreover, travel restrictions between cities during the public religious holidays were also set up to prevent mass gatherings of people traveling from the big cities to rural villages. Other measures including the stay-at-home recommendation, public transport restriction, and restriction on gatherings remained in place throughout the study period. The highest positivity rates were observed during the months of September 2020, May 2021, and July 2021 at 3.1%, 3.2%, and 3.0%, respectively.

Figure 2.

COVID-19 testing and cases in children with the implemented control measures between June 2020 and July 2021.

4. Discussion

Among the 38 provinces of Indonesia, North Sumatra Province has had the ninth highest number of COVID-19 cases in the country. As of September 30, 2022, it had contributed 2.5% of all COVID-19 cases, with a total of 127 325 cases recorded. Of these, 13.8% were reported in children, with a proportion of deaths of 1.2% [4]. This study examined the numbers of COVID-19 cases in children at the beginning of the pandemic. During the 14-month observation period, a total of 117 650 samples were tested in the centralized laboratory in North Sumatra Province, and 2222 (.6.4%) of 13 136 children tested were confirmed positive. This positivity rate is higher than those reported in aprevious epidemiological studies in Italy(1.2%) and the United States (1.7%)[5][8], despite the potential under-testing of COVID-19 in Indonesia [6], especially among children, who are more likely to present with an asymptomatic infection.

In 2020, young adolescents aged 12–14 years made up the greatest proportion of those who were infected with SARS-CoV-2, while thischanged to the age group of 6–11 years in 2021. However, during the observation period, all age groups were found to have been exposed to SARS-CoV-2, including children aged 0–5 years. Nevertheless, the proportion of infected children was lowest in the age group 0-5 years across the study period. These findings are similar to those reported from China, where the greatest proportion of infected children were in the age group 6–11 years (24.4%), followed by the age group 11–15 years (19.3%) [7]. This suggests that all ages in childhood are susceptible to SARS-CoV-2 infection. Adolescence has been linked to a higher risk of transmission due to several factors such as higher mobility, lower severity/asymptomatic, feeling invulnerable, less likely to adhere to intervention policies, and more likely to have social interactions regardless of the health consequences [8,9].

It was found in this study that the incidence of COVID-19 in children peaked during certain months, including September 2020, May 2021, and July 2021. These increases in infection transmission might be related to several factors, including an increase in gatherings in the community, leading to a higher exposure to children. For example, the Eid al-Fitr celebration occurred during the month of May 2021, and despite the control measures implemented, increased numbers of cases were observed both in adults and children during this month. However, the increase in cases in July 2021 was more likely to have occurred due to the introduction of a new variant of SARS-CoV-2 (Delta variant), which then predominated. The Delta variant was first reported to be circulating in children in North Sumatra Province in late June 2021, before it became dominant in mid-July [10]. The Delta variant has been reported to present with higher viral loads compared to other variants, and is therefore more likely to be highly transmissible [11,12].

This study showed the trend in COVID-19 in the paediatric population and the relationship with the control measures implemented in North Sumatra Province. However, there are several limitations to this study. First, although data from large numbers of children in the province are presented, the study did not collect data on the symptoms, disease severity, and outcomes of the children. Therefore, despite the high numbers of cases that are reported, no conclusions could be made on the health impact of COVID-19 on children. Second, the study was also done during the first year of COVID-19 pandemic when thepreventive control measures especially those impacting children (i.e. public school closure) were implemented throughout the study period. Therefore, it was not possible to evaluate whether the relaxation or reinforcement of certain interventions had an effect on increased transmission in children. Although this measure does not guarantee the protection of children from infection, it was only possible to conclude that the increased incidence of infection in children was mainly due to the introduction of new variants.

In conclusion, COVID-19 has been detected in all age groups of children in North Sumatra. During the study period, the incidence was found to peak due to mass gatherings, public holidays, and the introduction of a new variant in Indonesia. Children accounted for a much higher proportion of cases than those reported elsewhere during the pandemic peak, and they could have played a role as the source of transmission in society.