How to increase the effectiveness of booster shots

Miscellaneous / by admin / April 25, 2022

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It seems that our body prefers variety.

At the European Congress of Clinical Microbiology and Infectious Diseases, which is currently taking place in Austria, the results of an analysis of the Chilean COVID-19 vaccination program were presented. They are showedEffectiveness of homologous and heterologous booster doses for an inactivated SARS-CoV-2 vaccine: a large-scale prospective cohort study / The Lancetthat the efficiency of heterologous booster vaccinations is significantly higher than that of homologous ones. In other words, using a different vaccine for the third dose provides better protection than a booster with the same product used for the primary vaccination.

The study evaluated the effectiveness of booster vaccines CoronaVac (Sinovac Biotech), AZD1222 (Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) in people who have already received biphasic vaccination CoronaVac. Data from the National Vaccination Database of Chile were used for the analysis.

For the study, 4,127,546 profiles were selected for people who previously received two main doses of CoronaVac and were not sick with COVID-19, and during the study received a third booster dose. 1,921,340 people (46.5%) received an Oxford-AstraZeneca booster, 2,019,260 (48.9%) received a Pfizer-BioNTech booster, and only 186,946 (4.5%) chose CoronaVac again. They were observed from February 2 to November 10, 2021.

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Based on the data obtained, the authors calculated the adjusted efficacy of the vaccine (using statistical modeling) in preventing symptomatic COVID-19. The adjusted efficacy of the vaccine against hospitalization, the need for intensive care, and COVID-19-related death was 86%, 92% and 87% for the CoronaVac booster, 96%, 96% and 97% for the Pfizer-BioNTech booster and 98%, 99% and 98% for the Astra Zeneca booster respectively.

Our results show that the third dose of CoronaVac, or the use of another booster vaccine such as Pfizer-BioNTech or Astra Zeneca, in those who previously received two doses of CoronaVac provides a high level of protection against COVID-19, as well as severe illness and death if diseases.

However, receiving a different vaccine for a booster dose results in higher vaccine efficacy than third dose of CoronaVac, for all outcomes, further confirming the effectiveness of the mixing method vaccines.

Research excerpt

The weak effectiveness of identical boosters is also confirmed by a study by American scientists, the results of which publishedDurability of BNT162b2 vaccine against hospital and emergency department admissions due to the omicron and delta variants in a large health system in the USA: a test-negative case–control study / The Lancet The Lancet 22 April. The authors found that a third booster dose of a homologous mRNA vaccine (in this case Pfizer-BioNTech) reduced the risk of hospitalization and complications of omicron for only three months, after which its effectiveness is significantly decreases.

The Chilean government already recommends a third booster shot with a heterologous vaccine, but if desired, the vaccinated person can choose a homologous one.