- Antibody levels dropped off in the first 3 months after the 2nd dose: Study
- ‘Antibody level a very good indicator of protection against severe COVID’
- Researchers tested the ability of antibodies to block entry of the virus
London: A third dose of COVID-19 vaccine increases the level of antibodies that can effectively neutralise the Omicron variant of coronavirus, according to a study published in The Lancet journal. Researchers from Francis Crick Institute and the National Institute for Health Research (NIHR), UK, found that antibodies generated in people who had received only two doses of either the AstraZeneca or the Pfizer vaccine were less able to neutralise Omicron as compared to Alpha and Delta variants. They also found that antibody levels dropped off in the first three months following the second dose but a third ‘booster’ dose raised levels of antibodies that effectively neutralise the Omicron variant.
The study found that in people who had received the Pfizer vaccine for all three doses, antibody levels against Omicron after a third dose were similar to those previously reached against Delta after only two shots.
Overall, antibody levels were nearly 2.5 times higher against Omicron after three doses compared to after two jabs, according to the researchers.
Higher levels of antibodies against Omicron were also found in people who received two doses of either vaccine and also reported previously having COVID-19 symptoms, compared to those who didn’t have disease symptoms in past.
While levels of antibodies alone do not predict vaccine effectiveness, they are a very good indicator of protection against severe COVID-19, the researchers noted.
The study confirms that three doses of COVID-19 vaccine are essential to boost antibodies to quantifiable levels and maximise the amount of protection against severe disease and hospitalisation.
People who have queued outside vaccinations centres should be reassured that a vaccine booster is the best way of protecting them from Omicron, said Emma Wall, an infectious diseases consultant at UCLH Biomedical Research Centre of NIHR.
“And for people who haven’t yet had a booster or even a first dose, it’s not too late,” Ms Wall said in a statement.
The researchers analysed 620 blood samples from 364 people who enrolled in the study.
They tested the ability of antibodies to block entry of the virus into cells, so called ‘neutralising antibodies’, against different variants of SARS-CoV-2, including Omicron.
The researchers also included synthetic neutralising antibodies that are currently in use for COVID-19 treatment to test if they have neutralising activity against variants of SARS-CoV-2.
The team found that Xevudy (sotrovimab), a recently-approved synthetic monoclonal antibody used to prevent and treat patients at risk of developing severe COVID-19, was able to neutralise the Omicron variant. “We have really important early data to suggest that at least some versions of synthetic antibodies that we currently use to treat certain patients, are likely to be effective against this new variant,” Bryan Williams, UCLH Director of Research, added.
David LV Bauer, from Francis Crick Institute, said while Omicron has considerably more mutations than other recent variants, such as Alpha and Delta, the study shows that the boosters push the immune system to make a broad response capable of tackling it.
This new variant can overcome the immune blockade put in place by two vaccine doses, but thankfully following the third dose, neutralising activity is robust in the vast majority of people, Ms Wall said.
“A third dose builds our defences higher, making it harder for the virus to cause severe COVID-19,” she explained.
(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.