A team of scientists from the UK has recently explored the impact of non-pharmaceutical control measures and vaccination on the coronavirus disease 2019 (COVID-19) pandemic during school reopening in England. The findings reveal that vaccination of children over the age of 12 can significantly reduce infections and deaths. In the absence of vaccination, the continuous implementation of non-pharmaceutical control measures in schools can also have a positive impact.
Since the beginning of the COVID-19 pandemic, when no prophylactic interventions were available, non-pharmaceutical control measures (mask-wearing, physical distancing, travel restriction) have played a central role in controlling the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, many vaccines with good efficacy against SARS-CoV-2 infection and symptomatic COVID-19 are available globally, giving rise to a hope of an end to the pandemic.
COVID-19 vaccination programs began in the UK in December 2020, with an initial prioritization for older and high-risk populations. Later on, the offer was extended to individuals aged 16 years or above. The government removed restrictions on some non-pharmaceutical control measures with increasing vaccine coverage, leading to a sharp rise in new cases and mortality. This highlights the importance of non-pharmaceutical measures in controlling the pandemic trajectory, especially in schools where a significant proportion of children are under the age of 16 years and remain unvaccinated.
In the current study, the scientists have explored how vaccination and non-pharmaceutical control measures in schools can impact the growth of the COVID-19 pandemic in England.
The scientists used an individual-based model (JUNE) to simulate different situations and compare the relative importance of vaccination and non-pharmaceutical control measures. The model simulated the movements of the entire England population, including household, school, workplace, and recreational interactions. In the simulation analysis, they assumed that the delta variant of SARS-CoV-2 was dominantly circulating in England.
To assess the impact of vaccination, they assumed that 80% of the adult population are fully vaccinated together with vaccination of 80% of individuals aged 12 to 17 years and 16 to 17 years and all children.
Similarly, to assess the impact of non-pharmaceutical control measures in school, they assumed that all classmates undergo home isolation for ten days when a student develops COVID-19 related symptoms. Moreover, they considered the variation in contact frequency between students in school.
The scientists estimated infections and deaths by considering several situations with different vaccination coverage and a lack of non-pharmaceutical control measures. The findings revealed that school reopening with 80% vaccine coverage of adults or older teens (16 to 17 years) could lead to a 4 to 5-fold increase in daily COVID-19 cases and related mortality. Furthermore, it was predicted that the infection and mortality rates could be reduced, and the peak magnitude can be delayed by two weeks by vaccinating most teenagers (age: 12 to 17 years). Interestingly, a significant improvement was observed when all children were considered vaccinated (12 to 17 years).
Specifically, the findings showed that vaccination of children over the age of 12 could reduce the total number of infections by 2-fold compared to that observed when only adults are vaccinated. The same approach could also reduce the total number of deaths by 5000.
Regarding non-pharmaceutical control measures, the findings revealed that the number of deaths could be reduced significantly by reducing contact frequency between students (social distancing). Moreover, a significant reduction in death rate was observed for a situation where all classmates undergo home isolation upon detection of a single symptomatic case. Mask wearing together with social distancing and increased ventilation showed a similar positive impact on mortality.
The study highlights the importance of vaccination in controlling infection and mortality rates in England during school reopening. As observed in the study, schools can be a potential source of SARS-CoV-2 infections that can spread in the community. Another important finding is that implementing non-pharmaceutical control measures in schools can significantly impact population-level mortality.
As suggested by the scientists, the best possible way to control the pandemic trajectory is mass vaccination and the implementation of non-pharmaceutical control measures.