How effective is a COVID-19 vaccine booster dose?


vaccine vial

With the emergence of new variants of the SARS-CoV-2 virus, there is some concern that vaccine induced immunity will not be as effective. There is some debate over whether or not COVID-19 vaccine boosters will make any difference.

A study conducted in Israel set out to test whether booster shots with the Pfizer-BioNTech mRNA vaccine had any impact on deaths due to COVID-19.  

The study included people who were 50 years or older, who were divided into two groups. The first group that received booster doses of the COVID-19 vaccine, and the second group who did not receive a booster dose.

Using electronic medical records, the researchers were able to determine whether patients were infected with COVID-19, had any risk factors, and were able to identify patients who died due to COVID-19 during the study period. 

The researchers compared deaths that occurred due to COVID-19 between the group that received boosters and the group that did not receive boosters. 

Deaths due to COVID-19 were reported to be higher in the group that did not receive a booster dose, compared to those who did receive a booster. This effect was more pronounced in patients that were over the age of 60.

According to the study, in patients 50 years or older, “those who received a booster had 90% lower mortality due to Covid-19 than those who did not receive a booster.”

The researchers also compared the incidence of positive COVID-19 test results between booster and non-booster groups.  

Infection with SARS-CoV-2 also occurred in more people that did not receive a booster, compared with those that did receive a booster. 

The study concluded that “participants who received a booster at least 5 months after a second dose of BNT162b2 had 90% lower mortality due to Covid-19 in the short term than participants who did not receive a booster. However, studies with longer-term follow-up periods to assess the effectiveness and safety of the booster are still warranted.”

Reference: Arbel R, Hammerman A, Sergienko R, Friger M, Peretz A, Netzer D, Yaron S. BNT162b2 Vaccine Booster and Mortality Due to Covid-19. N Engl J Med. 2021 Dec 8. doi: 10.1056/NEJMoa2115624. Epub ahead of print. PMID: 34879190.

Image by cromaconceptovisual from Pixabay 

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