- The results were confirmed in a population of almost 4 million individuals
- 89% protection against severe COVID-19 after a month of vaccination: Study
- The protection reduces to 64% from four months and onwards: Study
London: The vaccine-induced protection against SARS-CoV-2 infection wanes within a few months, but protection against severe COVID-19 appears to be better maintained, according to a study published in The Lancet journal. Researchers noted that the protection wanes at different speeds depending on the type of vaccine used.
“The bad news is that the protection against infection seems to be diminished by seven months after the second dose of vaccine,” said Peter Nordstrom, a professor at Umea University in Sweden.
The good news, however, is that the protection against a severe infection that leads to hospitalisation or death seems to be better maintained. Vaccination is therefore very wise and important, Peter Nordstrom said.
The study is a nationwide, observational study based on registry-data from the Public Health Agency of Sweden, the National Board of Health and Welfare, and Statistics Sweden.
The main analysis included almost 1.7 million individuals, and the results were confirmed in an even larger population of almost 4 million individuals.
The results showed that protection against infection of any severity waned progressively following the peak which occurred a month after the second dose.
Six months after vaccination, the remaining protection against infection was 29 per cent from two doses of Pfizer, and 59 per cent from two doses of Moderna vaccine.
There was no remaining protection from a month and onwards for AstraZeneca, the researchers said.
With respect to infections that were severe enough to warrant a hospital stay, or where the individual died within 30 days of confirmed infection, the protection was better maintained, they said.
The study found that protection against severe disease was 89 per cent after one month and 64 per cent from four months and onwards during the rest of the maximum follow-up of nine months. “The results underscore and support the decision to offer a third dose,” said Marcel Ballin, doctoral student at Umea University and co-author of the study.
In particular, the results show that it was correct to prioritise the oldest and frailest individuals, Marcel Ballin said.
Prior to this study, a few observational studies and follow-up studies of the clinical trials have investigated waning vaccine protection in other countries.
However, these have mostly covered the initial four to six months, and for the Pfizer vaccine.
What this study contributes with is the longer follow-up time and the fact that we were able to explore how well the protection is maintained according to different types of vaccines, said Anna Nordstrom, adjunct professor at Umea University, and co-author of the study.
“The strengths are that we have been able to do this in a real-world setting based on a population-based sample of the total population of Sweden. This increases the possibility to generalise the results to other countries with similar population structure as in Sweden,” Anna Nordstrom added.
(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.