This is an archive article published on April 25, 2022

Vaccinated and never infected with Covid-19: Third dose can boost your immunity

The study published recently in the Journal of Infection has looked into the IgG and neutralizing antibody response in individuals vaccinated with two doses of Covishield vaccine against B.1, Delta, Beta and Omicron variants of the virus.

3 min readPuneUpdated: Apr 26, 2022 03:52 AM IST

A senior citizen getting vaccinted with the booster dose of Covid-19 vaccine in Ludhiana. (Express photo by Gurmeet Singh)

A new study by the Indian Council of Medical Research and National Institute of Virology has made a strong case for the administration of a precautionary third dose of the Covid-19 vaccine to boost immunity. The recommendation is particularly for people who have been vaccinated but not infected with the coronavirus in the past two years.

The researchers associated with the study compared three groups of people – ‘naïve vaccinees’, that is those who have taken the vaccine but have not been infected with Covid; individuals who have recovered from Covid-19 and who had taken two doses of the vaccine; and finally, individuals with SARS-CoV-2 breakthrough infection, that is those who contracted the virus after taking both the jabs.

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“Our study demonstrated lower IgG (Immunoglobulin, a type of antibody) and Nab (neutralizing antibody) response in naïve vaccinees than other groups. This emphasises the waning immune response in naïve vaccinees post second dose and warrants the administration of precautionary dose to boost immunity,” researchers associated with the study told The Indian Express.

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The study published recently in the Journal of Infection has looked into the IgG and neutralizing antibody response in individuals vaccinated with two doses of Covishield vaccine against B.1, Delta, Beta and Omicron variants of the virus.

The neutralising antibody is responsible for defending cells from pathogens. They are produced by the body as part of its immune response and their production can be triggered by an infection or vaccination against an infection. Immunoglobulin, also known as antibodies, are essentially glycoprotein molecules produced by white blood cells. They act as a critical part of the immune response by specifically recognising and binding to bacteria or viruses and helping to destroy them.

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“Despite the fact that vaccines are effective against severe SARS-CoV-2 infection, many breakthrough and re-infection cases were observed during the pandemic. The shifting paradigm would be mainly due to the reducing/waning immune responses post either natural infection or vaccinations, emergence of the new SARS-CoV-2 variant and its immune escape potential,” the researchers pointed out in the study.

Anuradha Mascarenhas

Anuradha Mascarenhas is a Senior Editor at The Indian Express, based in Pune. With a career spanning three decades, she is one of the most respected voices in Indian journalism regarding healthcare, science and environment and research developments. She also takes a keen interest in covering women's issues . Professional Background Education: A gold medalist in Communication and Journalism from Savitribai Phule Pune University and a Master’s degree in Literature. Author: She authored the biography At The Wheel Of Research, which chronicles the life and work of Dr. Soumya Swaminathan, the former Chief Scientist at the WHO. Key Focus: She combines scientific accuracy with storytelling, translating complex medical research into compelling public and human-interest narratives. Awards and Recognition Anuradha has won several awards including the Press Council of India's national award for excellence in journalism under the gender based reporting category in 2019 and the Laadli Media award (gender sensitivity -2024). A recipient of the Lokmat journalism award (gender category-2022), she was also shortlisted for the RedInk awards for excellence in journalism-2021. Her debut book At The Wheel Of Research, an exclusive biography of Dr Soumya Swaminathan the inaugural chief scientist of World Health Organisation was also nominated in the Popular Choice Category of JK Paper AUTHER awards. She has also secured competitive fellowships including the Laadli Media Fellowship (2022), the Survivors Against TB – New Research in TB Media Fellowship (2023) and is part of the prestigious 2025 India Cohort of the WomenLift Health Leadership Journey.” Recent Notable Articles (Late 2025) 1. Cancer & Specialized Medical Care "Tata Memorial finds way to kill drug-resistant cancer cells" (Nov 26, 2025): Reporting on a breakthrough for triple-negative breast cancer, one of the most aggressive forms of the disease. Discipline, diet and purpose; How a 97-year-old professor defies ageing'' (Nov 15, 2025) Report about Prof Gururaj Mutalik, the first Head of Department at Pune's B J Government Medical College who at 97 credits his longevity to healthy habits and a strong sense of purpose. 2. Environmental Health (The "Breathless Pune" Series) Long-term exposure even to 'moderate' air leads to chronic heart, lung, kidney issues" (Nov 26, 2025): Part of an investigative series highlighting that even "safe" pollution levels are damaging to vital organs. "For every 10 µg/m3 increase in PM2.5 level, there was 6-8% jump in medicine sales" (Nov 23, 2025): Using commercial data to prove the direct link between air quality and respiratory illnesses in Pune. 3. Lifestyle & Wellness News "They didn't let cancer, diabetes and heart disease stop them from travelling" (Dec 22, 2025): A collaborative piece featuring survivors who share practical tips for traveling with chronic conditions. At 17, his BP shot up to 200/120 mmHG; Lancet study flags why child and teen hypertension doubled between 2000 and 2020'' (Nov 12,2025)--A report that focusses on 17-year-old-boy's hypertensive crisis and reflects the rising global trend of high blood pressure among children and adolescents. 4. Scientific Recognition & Infrastructure For promoting sci-comm, gender diversity: IUCAA woman prof highlighted in Nature" (Nov 25, 2025): Covering the global recognition of Indian women scientists in gender studies and physics. Pune researchers find a spiral galaxy like the Milky Way from early universe'' (December 3, 2025)- A report on how Indian researchers discovered a massive galaxy that existed when the universe was just 1.5 billion years old , one of the earliest to have been observed so far. Signature Beat: Health, Science & Women in Leadership Anuradha is known for her COVID-19 reportage, where she was one of the first journalists to provide detailed insights into the Covishield and Covaxin trials. She has a dedicated interest in gender diversity in health and science, often profiling women researchers who are breaking the "leaky pipeline" in STEM fields. Her writing style is scrupulous, often featuring interviews with top-tier scientists and health experts from various institutions. ... Read More

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