A study done by faculty members of a government medical college says that nearly one in nine healthcare workers contracted COVID-19 infection, even after receiving both shots of a vaccine.
The study is yet to be peer reviewed and has currently appeared in preprint on an online platform. As per the study done by faculty of Delhi government’s Maulana Azad Medical College (MAMC), 36 of 326 healthcare workers at a Delhi hospital, who were part of the study, had breakthrough COVID-19 infections.
Breakthrough infections are occurrences of COVID-19, 14 days after taking both doses of a vaccine.
“A total of 36 breakthrough infections were reported in the HCWs (healthcare workers)… Furthermore, COVID-19 infections occurred in 65 HCWs vaccinated with at least one dose of vaccine but prior to receiving their second dose or <14 days post second dose,” a preprint of the study published online read.
“Most breakthrough infection cases [94.4%] were mild and did not require supplemental oxygen therapy. Conclusion: nearly one in nine HCWs experienced a COVID-19 breakthrough infection in the present study,” it further read.
The study also said that the HCWs with a past history of natural COVID-19 infection and later recovered, were 4.5 times less likely to experience a COVID-19 infection after partial vaccination.
“Variant strains may be by passing the immunity created by the vaccine. So, even after vaccination we have to take precautions,” said Pragya Sharma, professor at Department of Community Medicine of MAMC, who is one of the authors of the study.
The preprint said that a cross-sectional analysis was conducted at a medical college and hospital complex in Delhi through telephonic interviews among HCWs who had received at least one dose of a COVID-19 vaccine during January to March.
“These findings suggest that in real-world settings, a significant proportion of vaccinated individuals with high risk of exposure remain vulnerable to COVID-19 infection albeit with reduced disease severity in most cases,” the report said.
In this study, a history of a natural infection and recovery, was observed to be protective against a subsequent COVID-19 infection or reinfection in HCWs who had been administered at least a single dose of COVID-19 vaccine.
The study also warned that since infection status of the HCWs was based on self-report, mostly symptomatic breakthrough infections diagnosed with RT-PCR test were likely to be captured, while asymptomatic infections were potentially omitted.