Influence of post-exposure BNT162b2 prophylaxis towards SARS-CoV-2 infections

In a current examine posted to the medRxiv* preprint server, researchers decided proof for post-exposure vaccination in lowering the mortality charge of coronavirus illness 2019 (COVID-19). Researchers concluded that post-exposure prophylaxis efficiently decreased extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated dying charges. 

Study: BNT162b2 post-exposure-prophylaxis against COVID-19. Image Credit: Rido/ShutterstockExamine: BNT162b2 post-exposure-prophylaxis towards COVID-19. Picture Credit score: Rido/Shutterstock


A number of medicine comparable to remdesivir, nirmatrelvir, dexamethasone, anti-interleukin-6 receptor antibody, and sure investigational medicine like molnupiravir have been used for the therapy of COVID-19. Nonetheless, these therapy methods solely confer suboptimal therapeutic responses in direction of SARS-CoV-2 infections. Therefore additional therapeutic interventions are required for lowering COVID-19-associated mortality.  

Put up-exposure vaccination prophylaxis is a possible medical method in COVID-19 that has been used beforehand towards sure ailments. Put up-COVID BNT162b2 vaccination is of prime significance as a result of waning immunity following BNT162b2 vaccination. Nonetheless, no research have been revealed so far exploring post-exposure BNT162b2 vaccination prophylaxis in COVID-19.

In regards to the examine

Within the current observational examine, the effectiveness of the post-exposure BNT162b2-prophylaxis method towards the medical outcomes of COVID-19 was estimated utilizing nationwide surveillance information from the Israeli Ministry of Well being (MoH) registry. Israeli residents aged 12 years or older who had been first-time polymerase chain response (PCR)-positive for SARS-CoV-2 from the beginning of the vaccination marketing campaign between twentieth December 2020 and seventh October 2021 had been included within the examine.

Participant information on gender, age, and dates of first optimistic PCR, hospital admission, discharge, and dying had been collected from the database. The participant’s id was saved confidential, and the examine was exempt from the knowledgeable consent requirement. Those that turned PCR-positive at or after six days of the primary dose of vaccination had been excluded.

The unintended post-exposure prophylaxis represented by just lately vaccinated sufferers who turned SARS-CoV-2 PCR-positive on the identical day or through the 5 consecutive days following vaccination (Group one) was in contrast with the unvaccinated management lot (Group two).

The management group was established by matching group one with the unvaccinated individuals utilizing variables comparable to age, gender, first PCR optimistic date, hospitalization date, and date of COVID-19-associated dying.

Examine outcomes had been primarily centered on SARS-CoV-2-associated dying inside 60 days of the primary optimistic PCR date, hospitalization within the COVID-19 designated division between two days earlier than and 21 days after the PCR-positive date, and the length of hospitalization.


The outcomes confirmed that among the many 271,710 Israeli residents who obtained the BNT162b2 (Pfizer) vaccine, 11,690 individuals had optimistic PCR outcomes on the identical day or inside 5 days of vaccination, representing group one or just lately injected group. No variations in demographic traits had been noticed after matching teams one and two.

COVID-19-associated mortality charges amongst contaminated 55 years or older group as much as 60 days of the primary optimistic PCR had been markedly decrease in group one than the group two, in all gender and age teams.

The mixed group of men and women aged 65 years or older reported 143 and 280 deaths amongst 1,413 just lately vaccinated and unvaccinated individuals, respectively, with an odds ratio (OR) and 95% confidence interval (CI) of 0.46 and 0.36-0.57, respectively.

A big discount within the dying charge was noticed within the mixed 55 to 64 years of age group, with eight and 43 deaths amongst 1322 just lately vaccinated and unvaccinated controls, with OR and 95% CI of 0.18 and 0.07-0.39, respectively.

Within the 55 years or youthful age group, the dying charge was very low, and a statistically vital distinction was noticed among the many vaccinated and management teams.

The mixed group of men and women aged 12 and 55 years reported 10 and 22 deaths among the many 8955 just lately vaccinated and unvaccinated teams, with OR and 95% CI of 0.45 and 0.19-0.99, respectively. No vital variations in mortality charges had been noticed when analyzing the individuals of the 12- and 55-years teams individually as a result of low occurrences of dying occasions in these teams.

The hospital admission of the mixed group of each genders aged 65 years or older was 321 and 430 amongst 1413 just lately vaccinated and management teams, with OR and 95% CI of 0.67 and 0.57-0.80, respectively. Equally, hospitalization within the 55-64 years mixed teams was 81 and 115 amongst 1,322 topics within the examine and management teams, with OR and 95% CI of 0.69 and 0.50-0.93, respectively.

Vaccination standing didn’t considerably affect the size of hospital keep. Male and aged sufferers had elevated length of hospital stays.


The examine findings demonstrated that the usage of post-exposure BNT162b2 vaccine-prophylaxis reduces COVID-19-associated mortality by 50%, particularly in high-risk aged sufferers.

Put up-exposure vaccination confirmed reductions in SARS-CoV-2-associated extreme respiratory signs comparable to a low stage of saturated oxygen (<93%), respiratory charge of greater than 18 breaths/minute, and chest X-ray displaying pulmonary infiltrates. Put up-COVID vaccination prophylaxis additionally prevents SARS-CoV-2-associated grownup respiratory misery syndrome, deterioration to pneumonitis, and COVID-19 transmission by lowering antiviral titer within the respiratory tract of contaminated people.

*Necessary discover

medRxiv publishes preliminary scientific reviews that aren’t peer-reviewed and, subsequently, shouldn’t be thought to be conclusive, information medical follow/health-related habits, or handled as established data.

Journal reference:

  • Zohar Shemuelian, Yehuda Warszawer, Omri Or, Sagit Arbel-Alon, Hilla Giladi, Meytal Avgil Tsadok, Roy Cohen, Galit Shefer, Antonello Maruotti, Giovanna Jona Lasinio, Eithan Galun. (2022). BNT162b2 post-exposure-prophylaxis towards COVID-19. medRxivdoi: material/10.1101/2022.01.07.22268869v1

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