Vaccination has been a very important shield to combat deadly diseases and infections for a long time. In the current COVID-19 situation, vaccination has been playing a pivotal role in the ongoing control process of the disease. This article elucidates through 3 major trials, the efficacy of the Pfizer/BioNTech or AstraZeneca/Oxford COVID-19 vaccines in reducing disease and hospitalisation.

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More than 141 million cases and 3 million deaths have been registered in more than 223 countries and territories worldwide since the start of the pandemic. India had recorded over 2,00,000 deaths due to COVID-19. Every year, vaccines prevent the death of millions. At present, vaccination is one of the most important clinical options for preventing COVID-related infection and death, particularly in the midst of a pandemic. Soon after the initial phase 3, safety and efficacy trials were released, the first COVID-19 vaccines were approved, and the United Kingdom was one of the first countries to do so. Three distinct trials tested the efficacy of reducing both symptomatic and asymptomatic diseases and associated hospitalisations with a single or two-dose of vaccinations Pfizer/BioNTech or AstraZeneca/Oxford COVID-19.

First research trial

SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) is a broad, multicentre, national study. In general, 25,661 adult health staff from 104 public hospitals in England were a part of the research. 35% had either been positive for COVID-19, were previously tested, or had an antibody to the virus. However, 65% did not have any. At the end of the follow-up on 5 February 2021, about 89% of participants were receiving one dose at least of COVID-19 (94% for Pfizer, 6% for AstraZeneca).

According to the study's results, vaccinations were 70% effective 21 days after the initial dose, and 85% efficient 7 days after the second dose. During the two-month follow-up cycle, unvaccinated personnel had 14 coronavirus infections per 10,000 person-days, opposed to 8 per 10,000 in their colleagues who had had at one vaccine dose at least 21 days prior and 4 per 10,000 in those who had acquired their second dose at least 7 days prior.

According to the authors, the vaccinations proved to be successful against the B.1.1.7 version. It does not, however, preclude all cases of infection. As a result, they request that healthcare staff need to wear personal protective devices and take appropriate measures when coming into contact with patients.

Second research trial

The effect of the Pfizer-BioNtech vaccine (BNT 162b2) on both symptomatic and asymptomatic COVID-19 infections was assessed in this study by researchers at Hull Teaching Hospitals in England. On April 24, 2021, the study's results were published in Clinical Infectious Diseases.

The researchers discovered that when vaccination with BNT162b2 rose from 8.3 per cent to 82.5 per cent, the infection incidence decreased in both symptomatic and asymptomatic COVID patients. Additionally, they stated that vaccination was associated with a substantial reduction in SARS-CoV-2 cases, both symptomatic and asymptomatic.

The investigators concluded that "single dose BNT162b2 (Pfizer vaccine) was associated with a substantial reduction in positive PCR for SARS-CoV-2 in each of these symptomatic and asymptomatic HCWs (healthcare workers), with the most drastic result observed in symptomatic disease. Positive test rates for LFD (lateral-flow device) testing appear to be unperturbed by vaccine rollout and may remain to be a valuable standard test in vaccinated cohorts”.

Third research trial

The University of Edinburgh researchers examined the correlation between the widespread roll-out of the first doses of Pfizer and AstraZeneca vaccines and hospitalisations for COVID-19 in this Scottish population-based analysis. The Lancet released the report on April 23, 2021.

The investigators used the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) registry to collect vaccine, primary treatment, coronavirus monitoring, and hospitalisation reports for 5.4 million individuals in Scotland who were enrolled at 940 general practice clinics, accounting for approximately 99 per cent of the population.

They discovered that the first dose of Pfizer vaccine was associated with a vaccine effect of 91% for preventing COVID-19 hospital admissions, 28–34 days after vaccination compared to 88 per cent for the AstraZeneca vaccine. Additionally, they discovered that although the study was limited to people aged 80 years and over, the efficacy of both vaccinations was comparable (83 per cent).

The authors concluded, "Massive roll-out of the BNT162b2 mRNA and ChAdOx1 vaccines resulted in significant decreases in the rate of hospitalisation for COVID-19 infection in Scotland". It is possible that any of the observed results were caused by residual confounding”.

The Lancet published research concluded that vaccination, even one or two doses, successfully reduces all symptomatic and asymptomatic diseases and associated hospitalisations, and they have emphasised the importance of wearing personal protective equipment.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.