Teen vaccinations may have reduced hospitalizations even with omicron, study says

The immunization of adolescents against Covid-19 may have reduced hospitalizations in the city of Rio de Janeiro even with the spread of the ômicron variant, a new study points out. Those over 12 years of age vaccinated accounted for a minimal proportion of hospitalizations, while children who were still at the beginning of the vaccination campaign almost represented the totality of more severe cases.

Published as a pre-print, that is, without review by other scientists, the research was signed by five Brazilian researchers.

The authorization of the vaccine for adolescents over 12 years old took place in June 2021 for the Pfizer immunizer.

For children as young as five, the drug was approved in December. In January of this year, Coronavac won approval to be used in children over six years of age.

Using data from the Ministry of Health, the researchers point out that 1,422 children died from Srag (severe acute respiratory syndrome) due to Covid-19 until December 4, 2021 – which represents 0.38% of deaths caused by the complication.

The percentage may even be considered low, but the researchers note that the number of children killed by Srag as a result of the coronavirus is eight times greater than the deaths by Srag caused by all other respiratory viruses.

“In a pandemic scenario, it is obvious that if you have an immunizing agent that reduces the possibility of the child being hospitalized or dying, it is interesting”, says André Ricardo da Silva, pediatric infectious disease specialist and professor at the UFF faculty of medicine ( Federal Fluminense University).

The study used data from 300 patients under the age of 18 who had Covid and were treated at two pediatric hospitals in the capital of Rio de Janeiro — Prontobaby and Centro Pediátrico da Lagoa.

Of this total of hospitalizations, 240 patients were admitted between 2020 and 2021 in the period when no one under 18 years of age was fully immunized. According to the study, two-dose protection in the city with Pfizer was only achieved on December 30, 2021 in teens over 12 years old.

The other 60 patients were hospitalized from January to February 10 of this year, when there was already wide coverage of vaccination for adolescents over 12 years old, but there was still a lack of a consolidated campaign for the younger ones.

Severe cases of Covid in 2022 occurred mainly in the share of children who were at the beginning of the vaccination campaign, that is, those under 12 years old – in 2020 and 2021, there was a greater balance in the distribution of these occurrences between age groups.

“[Foram] very few hospitalized children over 12 years old, only five. And of those five, only two had received a complete outline. That is, of the 60 children who were hospitalized, 58 did not have the doses on the calendar”, says Silva.

As the second period of analysis took place in January 2022, it was also possible to analyze the impact of the ômicron variant, which spread across the country at the beginning of the year.

According to Silva, it is possible to say that, even with the variant, vaccination brought protection against hospitalizations for adolescents, since those immunized in this age group represented only two among the 60 hospitalized.

However, the doctor says that there was no genetic sequencing and therefore it is not possible to say with certainty how many of these 60 young people had been infected by the new variant.

The research joins other studies that have shown the vaccine’s effectiveness in preventing severe cases of Covid in children and adolescents.

Now, the researcher is already aiming to do a similar analysis aimed at younger children, as the vaccination campaign progresses.

But there is already a positive sign, he says. “We are already seeing, at this moment, practically no children hospitalized with Covid, even with the return to school”, she says.