A cross-sectional study by the state Health Department of 8,266 patients infected with Covid-19 at the height of the third wave showed the death rate among those vaccinated was 0.66% while the mortality rate among the unvaccinated was higher. three times higher, at 2.1%. The study also indicates that although the rate of breakthrough infection among vaccinated recipients was high, the severity of infection was lower than in unvaccinated people.
Out of 8,266 Covid-19 infected patients interviewed for the study in 36 districts, 943 were partially vaccinated, 4,359 had taken both doses while the remaining 2,964 were unvaccinated. The study found that 35 patients who were inoculated with one of the two available vaccines succumbed to the infection with a mortality rate of 0.66%. On the other hand, the fatality rate was 2.1% in unvaccinated patients with 63 deaths recorded during the investigation which ended on January 15.
This study was conducted to assess the impact and effectiveness of available vaccines among the infected population.
“Existing vaccines, which were designed for the original SARS-CoV-2, do not offer 100% protection against Covid-19 variants because its lasting response is not guaranteed. But as evidenced, they reduce the risk of hospitalization and death,” said Dr Avinash Supe, head of the Covid-19 death committee.
To date, the Center only authorizes vaccination for children over 15 years of age. For this reason, most infections, 21.83 percent, were recorded in the 11 to 20 age group, according to the study. Breakthroughs of infection among vaccinated people were mainly seen in young adults and the elderly – 31-40 years (19.31%), 41-50 years (17.33%) and 51-60 years (17 .11%).
Omicron, the new variant of SARS-Cov-2, which largely dominated its previous variant Delta during the third wave due to multiple mutations in its spike protein, is able to evade immunity against infections and previous vaccines.
Additionally, with the gradual decline in neutralizing antibody levels in vaccine-acquired individuals, infection breakthroughs increased further in fully vaccinated recipients who had taken their doses at the start of the mass vaccination program in January 2021. The study data showed that among the patients surveyed, 11.41% of breakthrough infections were recorded in those who received one dose and 52.73% in patients who took both doses.
“Several studies around the world have shown that the antibodies produced against SARS-Cov-2 gradually fade over time. Thus, the elderly and frontline people, who are most vulnerable to contracting Covid-19, have reported a higher number of breakthrough infections,” said Dr Gautam Bhansali, Head of Covid-19 Beds in private hospitals. “So the Center has given its approval for the booster injections. I think the government needs to extend it to the general population as well,” he added.
A pre-printed study by the UK Health Security Agency stated that the efficacy of the second dose vaccine against Omicron infection was 42.8%, which declined rapidly thereafter. Vaccine efficacy at the third dose was 94% and 67.7% against Delta and Omicron infection, respectively. However, the efficacy of the third dose vaccine against hospitalization with either Delta or Omicron was greater than 99%.
The state study also showed that a total of 504 patients surveyed who received one dose of the vaccine needed to be admitted, while 2,925 patients with both doses were admitted to hospital. Overall, 64.6% of people vaccinated with either dose required hospitalization. Of the unvaccinated patients, a total of 1,935 or 65.2% had to be admitted.
An analysis of the data showed that among the targeted patients, 55.9% of vaccinated patients were asymptomatic, compared to 60.6% of unvaccinated patients. But, public health officials observed, the risks of developing severity in unvaccinated patients, especially with comorbidities, were high, as 22 of those patients were found to be more critical than 14 of their vaccinated counterparts.
“The third wave bears witness that vaccines help control severity in patients. Thus, the eligible population should receive their booster shots,” said state task force member Dr. Shashank Joshi.