A new study published in the New England Journal of Medicine is offering some of the first real-world data on COVID-19 vaccine effectiveness against the Omicron variant in children aged 5 to 11. The findings reveal vaccination reduce a child’s risk of severe illness and hospitalization by two-thirds compared to unvaccinated children.
The study looked at 1,185 children admitted to hospital due to COVID-19 between July 2021 and February 2022. About 900 adolescent subjects were aged between 12 and 18 and the remainder were children aged between 5 and 11. In the older adolescent cohort 87 percent of hospitalizations were unvaccinated and 92 percent of hospitalized children between 5 and 11 were unvaccinated.
Looking more specifically at the effect of vaccination against Omicron, the study estimated two mRNA vaccine doses in children aged 5 to 11 were 68 percent effective at preventing hospitalization. More data was available for the older adolescent cohort, with the researchers estimating vaccination was 79 percent effective at preventing severe disease (defined as critical illness during hospitalization) from Omicron, but only 40 percent effective at preventing hospitalization.
“The reason for a child to get a COVID-19 vaccine is to prevent severe complications of SARS-CoV-2 infection, including hospitalization,” said Adrienne Randolph, from the Boston Children Hospital and co-lead on the new study. “This evidence shows that vaccination reduces this risk substantially in 5- to 11-year-olds. And while vaccination provided adolescents with lower protection against hospitalization with Omicron versus Delta, it prevented critical illness from both variants.”
The study does note there is evidence of increased vaccine breakthrough infections due to the emergence of the Omicron variant. However, the data indicates vaccine protection against critical illness remains high, affirming the value of vaccination in these age groups.
The benefits clearly outweigh the risks, as severe infections in childhood can have long-term consequences.
“Our findings support the premise that vaccination-induced immunity attenuated Covid-19 disease severity without fully eliminating the risk of breakthrough infections in vaccinated children and adolescents,” the researchers write in the study. “Although no such previous data are available for children, studies evaluating Covid-19 in vaccinated as compared with unvaccinated adults have shown similar disease attenuation.”
The researchers make clear the data in the study is still preliminary, as both age groups only received emergency authorization to access vaccinations in mid-to-late 2021. The data also only covers two-dose vaccinated subjects, with boosters yet to be widely administered in either cohort. And adult data has demonstrated three vaccine doses seem to be crucial for effective protection against the Omicron variant.
Randolph said she hopes the new data helps inform parents as to the benefits of vaccinating children against COVID-19. Recent data from the Centers for Disease Control and Prevention (CDC) indicate little more than a quarter of US children aged between 5 and 11 and just over half of kids 12 to 17 are fully vaccinated.
“We hope our findings will help parents make the decision to vaccinate their children and teens against COVID-19,” said Randolph. “The benefits clearly outweigh the risks, as severe infections in childhood can have long-term consequences.”
The new study does not directly compare the risks of vaccine side effects in children to the protective benefits against COVID-19. In an audio interview accompanying the publishing of the study, deputy editor of the New England Journal of Medicine Lindsey Baden addresses those specific concerns. Baden said side effects of the vaccine in children are very rare and this new research clearly demonstrates the risks from COVID-19 in unvaccinated children are much greater.
"In my own reflection on this, the risk of a one-in-a-million or very rare side effect—be it the myocarditis or the anaphylaxis or some of these considerations which are still hard to understand given their rarity—versus the clear benefits of protecting against the illness, makes it a very easy decision," Baden said.
The new study was published in the New England Journal of Medicine.
Source: Boston Children’s Hospital