COVID boosters could lose peak effectiveness at 4 months, however nonetheless considerably enhance total safety, new research finds


A new study from the US Centers for Disease Control and Prevention has found that although protection against Moderna and Pfizer COVID-19 booster shots wanes after about four months, boosters still provide significant protection against SARS. -CoV-2 after that.

In the recent to study, published February 11, researchers analyzed 241,204 emergency department (ED) and urgent care center (UC) encounters related to COVID, as well as 93,408 hospitalizations in 10 US states. These cases occurred between August 2021 and January 2022, during which time omicron was the most contagious strain of COVID-19. In terms of protection against hospitalization, the study found that two months after the third vaccine, vaccine efficacy was 91%. After four months, it dropped to 78%. In terms of protection against visits to the ER or EC, vaccine effectiveness increased from 87% to 66% over the same period. It’s still better than no protection at all, but there is a definite decrease.

While there was many studies on the effectiveness of the first two COVID-19 vaccines, research on the levels of protection offered by a third vaccine has been limited. However, the rise of the highly infectious omicron variant has triggered the need for further research. According to the scientific journal NatureSeveral months after Israel became the first nation to make a third vaccine available to the public, a study found that older Israelis who received their third vaccine were significantly less likely to test positive for COVID-19 or develop life-threatening symptoms and related symptoms. illnesses than those who have only had their two main injections.

Like all studies, this one had some limitations. The main one being that the researchers only focused on people who were seeking medical treatment for COVID-19, meaning COVID-19 infections that did not require medical treatment were not counted in the results. data. This aspect means that research could be more oriented towards immunocompromised people or the elderly.

So, since we know that the third strike can give us additional protection against COVID-19 but it weakens over time, this begs the question: Will we need a fourth strike? “The finding that the protection conferred by mRNA vaccines declined in the months following receipt of a third dose of vaccine reinforces the importance of considering more additional doses to maintain or improve protection against COVID- 19, » the researchers said in the study. In some countries, a fourth shot has already been deployed to select groups of people. The CDC has already approved the idea of ​​fourth shots for immunocompromised people in the United States, as SELF previously reported. In France health authorities authorized a fourth COVID-19 vaccine for organ recipients who had not responded to the previous three doses. In Sweden a fourth vaccine was recently recommended for people over 80 and those residing in nursing homes. In the UK a fourth vaccine is offered to people aged 12 and over who have a severely weakened immune system.

For now, it is clear that even when vaccine and booster protection wanes, inoculation against COVID-19 remains the best bet to stay safe. « All eligible individuals should stay up to date with recommended COVID-19 vaccinations to better protect against COVID-19-associated hospitalizations and ED/UC visits, » the researchers said in the study.


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