The latest study of breakthrough infection by the Indian Council of Medical Research (ICMR) reveals crucial findings over the severity of Covid-19 disease among fully vaccinated individuals. The study, which was conducted over 274 people showed that only 27 (9.9%) of them required hospital care. However, it also recorded one death among the hospitalised participants.
The research recorded cases of breakthrough infection through passive and voluntary reporting at various healthcare facilities from different districts of Odisha. 361 samples were collected for the study between March 1 and June 10.
However, the research was continued with 274 subjects as the rest of the participants were either found not fully vaccinated or contracted the Covid-19 infection within 14 days of taking the second dose of vaccine.
The participants were divided into two groups based on the vaccines they were administered. Covishield takers were significantly higher (239) than Covaxin (35). In percentage, 12.8% of participants took Covaxin while Covishield was taken by 87.2% of participants.
The highlight of the research is the prevalence of symptoms among Covid-19 positive individuals post-vaccination. The study found that 83.2% of the participants were found to have symptoms.
Another highlight is the antibodies presence of the vaccines–Covishield and Covaxin–among the vaccinated individuals. While 258 (94.2%) individuals found exhibiting the antibodies post-vaccination, there was a significant difference in seropositivity among both the vaccines.
The Covishield group reported higher seropositivity as well as the antibody titers compared to the Covaxin group in the research.
“A total of 258 (94.2%) individuals were found to be positive for SARS-CoV-2 IgG antibodies against spike protein. There were significant differences in seropositivity between Covaxin (77.1%) and Covishield (96.7%). Recipients of Covishield showed higher median titre values than Covaxin among the reported cases which were statistically significant,” the study read.
Despite this, the symptoms arrived in both the vaccine groups with a negligible difference. The most common symptoms researchers found were fever (88.5%), cough (77.6%) and sore throat (59.6%).
Noted epidemiologist and expert in public policy & health systems, Dr Chandrakant Lahariya said that the study is limited but it provides a few early indications.
“Though the correlates of protection are not determined, the study provides an early indication that the higher the level of antibodies a vaccine provides, the better are the chances of not progressing to the severe stage, if Covid-19 contracts,” he weighed in.
Speaking on the effectiveness comparison between both the vaccines which was investigated in the study, Lahariya told The Statesman that comparison can not be drawn due to the statistical limitations of the study.
“The percentage of Covaxin group was much smaller. It won’t be appropriate to infer anything over their (vaccines) effectiveness,” he added.