Covid Booster Dose Effective In Reducing Severe Disease Outcomes: Lancet Study

Boston: A third dose of COVID-19 vaccine is effective in reducing severe disease outcomes compared to individuals who have received two doses at least five months ago, according to the largest real-world study of Pfizer booster shot published in The Lancet. The study by researchers from The Clalit Research Institute and Harvard University was conducted in Israel, an early global leader in third-dose COVID-19 vaccination rates.

It is the first to estimate the effectiveness of a third dose of Pfizer-BioNTech mRNA COVID-19 vaccine against severe outcomes with adjustment for various possible confounders, including comorbidities and behavioural factors.A recent clinical trial conducted by BioNTech included a smaller sample size and did not estimate the third-dose’s effects for more severe outcomes. The study took place from July 30 through September 23, 2021, coinciding with Israel’s fourth wave of coronavirus infection and illness, during which the Delta variant was the dominant strain in the country for most new infections.

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Researchers reviewed data from 728,321 individuals aged 12 or above who had received the third dose of the Pfizer vaccine. These individuals were carefully matched 1:1 with 728,321 individuals who had received only two shots of the Pfizer vaccine at least five months prior. Individuals were assigned to each group dynamically based on their changing vaccination status.

The results show that, compared with individuals who received only two vaccine doses five months prior, those who got three doses had 93 per cent lower risk of COVID-19-related hospitalisation, 92 per cent lower risk of severe disease, and 81 per cent lower risk of death. Vaccine effectiveness was found to be similar for different sexes, age groups and number of comorbidities, the researchers said.

The study also included a population-level analysis which found that infection rates began to drop for each age group 7-10 days after they became eligible for the third dose.

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“These results show convincingly that the third dose of the vaccine is highly effective against severe COVID-19-related outcomes in different age groups and population subgroups, one week after the third dose,” said Professor Ran Balicer, senior author of the study from Clalit Research Institute in Israel.

Professor Ben Reis from Harvard Medical School noted that one of the main drivers of vaccine hesitancy has been a lack of information regarding the effectiveness of the vaccine.

“This careful epidemiological study provides reliable information on third-dose vaccine effectiveness, which we hope will be helpful to those who have not yet decided about vaccination with a third dose,” Professor Reis said.

Professor Miguel Hernan from the Harvard T.H. Chan School of Public Health said the trial of the Pfizer vaccine provided compelling evidence of its effectiveness to prevent symptomatic infection, but the estimates for severe disease and specific age groups were too imprecise.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

NDTV – Dettol have been working towards a clean and healthy India since 2014 via Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity,  that is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.