In a review article in The Lancet, a team of international experts states that people who are not at risk do not need a third vaccine against Covid-19. Even in relation to the delta variant, the efficacy of the vaccine against serious diseases is so high that a so-called booster dose is not necessary for the whole population.
The report is published in The Lancet and examines the data available so far in scientific journals, from controlled studies and observational studies. The panel of experts includes researchers from the World Health Organization and the US Food and Drug Administration.
Consistent result One of the observational studies is that the vaccine still provides very good protection against serious diseases in all the different variants of the virus. On average, protection was 95% effective against serious diseases in both delta and alpha variants of the virus. Infection protection was over 80 percent for both variants.
For all different types of vaccines and virus variants, the vaccine provides better protection against serious illnesses than mild illnesses, according to the review article. The vaccine is also less effective against the spread of infection than against serious diseases. However, it is still vaccinated minorities who are leading the spread of the infection in populations where the vaccination rate is high, the report said. It is also these minorities who are most at risk of suffering from a serious illness.
– The studies that have been done so far do not provide any support that the protection against serious diseases will be significantly reduced. The limited supply of these vaccines will save more lives if offered to people at high risk for serious illness and who have not yet received a vaccine, says lead author Ana-Maria Henao-Restrepo, head of the WHO Vaccine Research Initiative Group. in a press release.
– Even if there is ultimately some benefit from a booster dose, it will not outweigh the benefits of offering the unvaccinated primary vaccine. If the vaccine is used where it is most useful, it can accelerate the end of the pandemic by preventing further development of new strains of the virus, Ana-Maria Henao-Restrepo continues.
The 18 researchers behind the review notes that even if antibodies decrease over time in vaccinated individuals, this does not necessarily mean that protection against serious diseases is reduced. This may be due to the fact that protection against serious diseases comes not only from antibodies, but also from memory cells of immune cells, including the so-called T cells.
If booster doses are still offered, the groups where the benefit outweighs the risk of possible side effects should be carefully identified, according to the research team.