Efficacy of COVID vaccines against death remains high in children, regardless of variant

Efficacy of COVID vaccines against death remains high in children, regardless of variant

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The efficacy of COVID-19 vaccines in preventing death remains high in children and adolescents regardless of the dominant variant in circulation, a large study published in Argentina shows. BMJ today.

Despite vaccine efficacy Researchers say vaccinating children is an important public health measure that will continue to prevent deaths, as infection declines sharply over time, especially during the omicron period.

It is already well known that mRNA and inactivated COVID-19 vaccines are effective in preventing serious illness and infections in children and adolescents, but data on deaths are lacking.

Decreased protection against infection has also been described, particularly for mRNA vaccines, but evidence for inactivated vaccines in children is limited.

To fill this knowledge gap, the researchers evaluated the efficacy of two mRNA vaccines (Moderna and Pfizer-BioNTech) and inactivated Sinopharm. inoculate Against COVID-19-related infection and death in children and adolescents and short-term weakening of immunity.

Their findings are based on data from 844,460 children and adolescents (3-17 years old) from the National Surveillance System and the Argentina Nominalized Federal Vaccination Registry.

Argentina began vaccinating adolescents (12-17 years old) in August 2021 and little children (3-11 years old) in October 2021.

Participants were grouped according to: vaccination status Before being tested for COVID-19 in a medical center (using a PCR or rapid antigen test) from September 2021 to April 2022, when delta and omicron BA.1 variants predominate in Argentina.

Fully vaccinated 12-17 year olds received two doses of Pfizer-BioNTech and/or Moderna vaccine, and fully vaccinated 3-11 year olds received two doses of Sinopharm vaccine. The mean time from second dose to test was 66 days for 12-17 year olds and 54 days for 3-11 year olds.

Positive testers (cases) were matched with negative testers (controls) based on age, gender, region of residence, week of testing, type of test, and current health conditions. After matching, 139,321 cases with their corresponding controls were included in the analysis.

The results show that the estimated vaccine efficacy against COVID-19 infection is 61% in children and 67% in adolescents in the delta period and 16% and 26% in the omicron period, respectively.

Vaccine efficacy decreased over time, particularly during the omicron period, from 38% at 15-30 days post-vaccination to 2% in children and from 56% to 12% in adolescents 60 days or later.

In the Omicron period, vaccine efficacy against death due to COVID-19 infection was 67% in children and 98% in adolescents.

This is an observational study and therefore cannot determine the cause. Researchers also admit that some information is missing, such as symptoms and hospitalizations. They cannot rule out the possibility that other unmeasured (confounding) factors may have influenced their results.

However, their results were consistent after further analysis to assess the effect of different tests and combinations of vaccines and were in line with the results of other similar studies, suggesting that they are likely to be robust.

This is why the researchers say that vaccination, regardless of the circulating variant, is effective in preventing death in children and adolescents with COVID-19.

Although vaccines are also effective in preventing COVID-19 infection in children and adolescents in the short term, there has been a significant decrease over time, especially during adolescence. omicron domination, they add.

«In summary, vaccinating children is an important public health measure that will prevent deaths in this population, especially during periods of high viral circulation.»

More information:
Efficacy of mRNA-1273, BNT162b2 and BBIBP-CorV vaccines against infection and death in children during prevalence of delta and omicron covid-19 variants in Argentina: test negative, case-control study, BMJ (2022). DOI: 10.1136/bmj-2022-073070

quotation: The efficacy of COVID vaccines against death is high in children regardless of variant (2022, 30 November), retrieved from https://medicalxpress.com/news/2022-11-effectness-covid-vaccines-death-high.html on 30 November 2022 continues to be.

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