<p>In a recent ICMR study, breakthrough cases after full vaccination with Covaxin have shown a significant increase in the immune response against coronavirus' variants of concern -- Beta, Delta and Omicron.</p>.<p>Individuals who recovered from Covid also showed significant immunity boost post-vaccination with Covaxin but lower than the breakthrough cases.</p>.<p>However, those who had taken two doses of Covaxin had very low neutralizing titres demonstrating the waning immunity after three months of the second dose of Covaxin, the study showed.</p>.<p>"The study highlights the significance of administering a booster dose or precaution dose of Covid vaccine as it provides better protection against the disease," Dr Pragya Yadav, a senior scientist at NIV Pune and the lead investigator of the study, told PTI.</p>.<p>The findings of the study, conducted in February this year after isolating the Omicron variant, have been published in the Journal of Infection on April 5.</p>.<p>"The impact of the third wave of the pandemic in India, caused by Omicron, triggered us to study the effectiveness of Covaxin against this variant.</p>.<p>"We assessed the sera of naïve, recovered and breakthrough cases vaccinated with Covaxin for its neutralising ability against Omicron and other variants," she stated.</p>.<p>As part of the study, participants were categorised into three groups -- 52 Covid-19 naïve individuals vaccinated with two doses of Covaxin with an average age of 41.7 years, 31 Covid-19 recovered cases vaccinated with two doses of Covaxin with average age of 41.7 years and 40 breakthrough cases after two-dose vaccination with Covaxin with an average age of 43.7 years.</p>.<p>The sera samples of naïve, recovered and breakthrough cases, were collected on average 97, 99 and 110 days, respectively.</p>.<p>The breakthrough infection was found to occur on average 43 days after the second vaccination.</p>.<p>A majority of the breakthrough cases had mild disease (95%) and two were asymptomatic, while 32.5% had co-morbidities like diabetes, hypothyroidism, hypertension, cardiac arrhythmias and allergic asthma.</p>.<p>"Breakthrough cases had the highest neutralising activity against all variants demonstrating a significant increase in the immune response post-infection. Recovered cases also showed significant immunity boost post-vaccination, but were lower than breakthrough cases.</p>.<p>"Apparently, the naïve cases had very low neutralizing titres against all the variants compared to the recovered and breakthrough cases," Dr Yadav stated.</p>.<p>The Omicron variant has shown a pronounced resistance to neutralization with the sera of all the three groups compared to B.1, Beta and Delta variants, she said. </p>.<p>Dr Yadav noted that Omicron was less effectively neutralized with the sera of naïve cases (12.9 fold) than recovered (7.98 fold) and breakthrough (8.84 fold) compared to B.1.</p>.<p>Although the immune response was less against the Omicron, it would still protect individuals from developing severe disease, hospitalization and mortality, she added.</p>.<p><strong>Watch latest videos by DH here:</strong></p>
<p>In a recent ICMR study, breakthrough cases after full vaccination with Covaxin have shown a significant increase in the immune response against coronavirus' variants of concern -- Beta, Delta and Omicron.</p>.<p>Individuals who recovered from Covid also showed significant immunity boost post-vaccination with Covaxin but lower than the breakthrough cases.</p>.<p>However, those who had taken two doses of Covaxin had very low neutralizing titres demonstrating the waning immunity after three months of the second dose of Covaxin, the study showed.</p>.<p>"The study highlights the significance of administering a booster dose or precaution dose of Covid vaccine as it provides better protection against the disease," Dr Pragya Yadav, a senior scientist at NIV Pune and the lead investigator of the study, told PTI.</p>.<p>The findings of the study, conducted in February this year after isolating the Omicron variant, have been published in the Journal of Infection on April 5.</p>.<p>"The impact of the third wave of the pandemic in India, caused by Omicron, triggered us to study the effectiveness of Covaxin against this variant.</p>.<p>"We assessed the sera of naïve, recovered and breakthrough cases vaccinated with Covaxin for its neutralising ability against Omicron and other variants," she stated.</p>.<p>As part of the study, participants were categorised into three groups -- 52 Covid-19 naïve individuals vaccinated with two doses of Covaxin with an average age of 41.7 years, 31 Covid-19 recovered cases vaccinated with two doses of Covaxin with average age of 41.7 years and 40 breakthrough cases after two-dose vaccination with Covaxin with an average age of 43.7 years.</p>.<p>The sera samples of naïve, recovered and breakthrough cases, were collected on average 97, 99 and 110 days, respectively.</p>.<p>The breakthrough infection was found to occur on average 43 days after the second vaccination.</p>.<p>A majority of the breakthrough cases had mild disease (95%) and two were asymptomatic, while 32.5% had co-morbidities like diabetes, hypothyroidism, hypertension, cardiac arrhythmias and allergic asthma.</p>.<p>"Breakthrough cases had the highest neutralising activity against all variants demonstrating a significant increase in the immune response post-infection. Recovered cases also showed significant immunity boost post-vaccination, but were lower than breakthrough cases.</p>.<p>"Apparently, the naïve cases had very low neutralizing titres against all the variants compared to the recovered and breakthrough cases," Dr Yadav stated.</p>.<p>The Omicron variant has shown a pronounced resistance to neutralization with the sera of all the three groups compared to B.1, Beta and Delta variants, she said. </p>.<p>Dr Yadav noted that Omicron was less effectively neutralized with the sera of naïve cases (12.9 fold) than recovered (7.98 fold) and breakthrough (8.84 fold) compared to B.1.</p>.<p>Although the immune response was less against the Omicron, it would still protect individuals from developing severe disease, hospitalization and mortality, she added.</p>.<p><strong>Watch latest videos by DH here:</strong></p>