Despite the pandemic, many cities around the world are still considering to reopen schools. But a recent study suggested that doing so would increase the chance of new COVID-19 clusters because children could spread the virus as well.
The role of children and teenagers in spreading SARS-CoV-2 to others was investigated by researchers at Korea Centers for Disease Control and Prevention, and Hallym University College of Medicine. Their findings showed that children could transmit the virus to other people, similar to adults do. Though, younger children were found less often to spread the pathogen, compared to adults. They published their findings in the journal Emerging Infectious Diseases (EID).
Can Children Spread COVID-19 to Other People?
There are multiple ways for highly contagious diseases to spread in human communities. From respiratory droplets to intimate physical contacts, pathogens use these means to get inside the human body. But for COVID-19, the SARS-CoV-2 virus is primarily transmitted via respiratory droplets emitted by someone infected. Face masks, social distancing, and proper handwashing are some methods to reduce the chance of transmission. These methods can decrease the risk of contracting and spreading the disease to others.
However, in school settings, these preventive methods may unlikely be followed at all times, especially by younger children. There are moments wherein someone unintentionally forgets a protocol or two, which is enough to increase the transmission risk of a person nearby. Yet studies in the role of children in spreading the disease are scarce. So, researchers in South Korea applied contact tracing to gain insights.
“I fear that there has been this sense that kids just won’t get infected or don’t get infected in the same way as adults and that, therefore, they’re almost like a bubbled population. There will be transmission. What we have to do is accept that now and include that in our plans,” said Michael Osterholm, an infectious diseases expert at the University of Minnesota, and who was not a part of the study, quoted American newspaper The New York Times.
In the study, the research team gathered the information of 59,073 contacts of 5,706 COVID-19 index patients via contact tracing. The index patients were reported in South Korea from January 20 to March 27, 2020. Numerous methods were applied in contact tracing including closed-circuit television, credit card transactions, and global positioning system, on top of the traditional epidemiological methods. While many would be concerned about privacy, the new contact tracing steps were adopted to better track down patients.
Researchers also described the public health system of the country. The national agency governing the system is the Korea Centers for Disease Control and Prevention. A total of 17 regional governments and 254 local public health centers coordinate information of COVID-19 patients with the national agency. The confirmation of patients was done through reverse-transcription polymerase chain reaction or RT-PCR test.
All contacts in the study were monitored for an average of 9.9 days after SARS-CoV-2 was confirmed. Out of 10,592 household contacts, 32.3% of index patients were aged between 20 and 29 years, 16.5% were aged between 40 and 49 years, and 19.3% were aged between 50 and 59 years. A total of 11.8% of household contacts had COVID-19. While out of 48,481 non-household contacts, only 1.9% had the disease. The figures showed that COVID-19 was statistically more significant in household contacts.
Results in analyzed records revealed that in 11.8% of household contacts with COVID-19, the rates were substantially greater for contacts of children than adults. The rates highlighted that once schools reopened; young students could transmit the virus to others. This indicated the potential role of children and teenagers in unknowingly spreading COVID-19. Because of the rates, researchers dug deeper to know more details.
They examined the rates of COVID-19 for household contacts of all school-aged children. Then, researchers compared the difference in rates between children and teenagers. Children aged nine years and younger could spread the virus at a much lesser rate at 5.3%, compared to the 18.6% rate among children older than nine years. The rates expressed the hypothetical risk of new COVID-19 clusters in schools as students might interact with each other. But they lacked the necessary data to support the hypothesis.
Previous studies conducted in Asia and Europe showed that children were less likely to be infected by COVID-19. However, some experts said that those studies were small and flawed to accurately explain pediatric cases. Fewer or not, children could still get sick from SARS-CoV-2 and governments should not underestimate it. If new clusters would start in schools, new clusters in communities might follow. The more students get the virus, the higher the chance the pathogen would penetrate households.
How Contagious is the Novel Coronavirus?
According to Statista, a German portal for statistics, the basic reproductive rate of SARS-CoV-2 was lower compared to other highly contagious viruses. As of January 23, 2020, its reproductive rate scored 1.4 to 2.5 or up to 2.5 individuals. It was outranked by measles at between 12 and 18, polio at five and seven, HIV at two and five, SARS-CoV-1 at two and five as well, and influenza at two and three. These rates were estimated by the World Health Organization (WHO) in the earliest month of COVID-19.
But a study published in EID in July 2020 showed a new estimated reproductive rate of SARS-CoV-2: more than twice the earlier estimate. To be fair, the July study had access to better data after COVID-19 infected millions of people globally. The data provided them sufficient information to calculate an updated estimate of the reproductive rate.
At the time of the Wuhan outbreak, the estimated rate was between 2.2 and 2.7 that are closer to the WHO’s. During that period, a doubling time of infected individuals was from six to seven days. With a new mathematical modeling and additional data, the doubling time was calculated to be between 2.3 and 3.3 days. Using an assumption of six to nine days of serial interval, the authors calculated a basic reproductive rate of 5.7. That means one person with COVID-19 could spread the virus to up to five people.
New policies in school reopening are required to reduce the transmission risk among students. These policies must include strict implementation of social distancing and frequent handwashing on top of personal protective items. Also, the policies should feature enhanced contact tracing of children infected with COVID-19.