In a reassurance to many who have received the Covid-19 vaccination, an evidence-based study released by Fortis Healthcare highlights that 92 per cent of fully vaccinated healthcare workers, amongst those who acquired Covid-19 infection post-vaccination, developed only mild Covid-19 infection, largely recovering under home care, despite a surge in serious infections during the second wave of the pandemic.
The findings of the study which has been released to understand the role of vaccines and severity of Covid-19 infection post-vaccination, addresses the vaccine hesitancy and also dispels myths related to vaccination. The study highlights that amongst those who tested Covid-19 positive post-vaccination, only one per cent of the fully vaccinated healthcare workers (HCWs) developed severe illness requiring ICU care/ventilator support. The study assessed around 16,000 healthcare workers who had been administered both first and second doses of vaccine between January and May this year. This period included the peak of the second wave, wherein India was recording 3.5 to 4 lakh cases each day and HCWs were working round-the-clock, spearheading the recovery of seriously infected patients.
The overall findings of the study emphasise that the vaccines available in India for Covid-19 are effective and offer protection against SARS-CoV-2 virus.
Key Findings of the Study
At least 92 per cent of healthcare workers (16,000) who received both the first and the second dose of the two-dose vaccine (fully vaccinated) did not face severe symptoms needing ICU care or resulting in mortality.
After receiving both the doses, only six per cent of the staff got infected.
The figures show that amongst those who got infected after getting fully vaccinated, 92 per cent were mildly infected cases and seven per cent developed moderate illness requiring oxygen support and only one per cent developed severe illness requiring ICU care and ventilation.
The ongoing studies suggest another important benefit of getting vaccinated. In addition to the direct effects of reducing risk of infection and reducing severity, vaccines may be associated with reduced likelihood of household transmission as well, thereby, preventing the spread of infection on to others. A new study by Public Health England (PHE) has shown that one dose of the Covid-19 vaccine (Pfizer-BioNTech or AstraZeneca vaccine) reduces household transmission by up to 50 per cent.
Commenting on the findings of the study, Dr Bishnu Panigrahi, Group Head, Medical Strategy and Operations Fortis Healthcare, said: “The study clearly brings out important findings that the vaccines available in India for Covid-19 do provide protection against the virus even among healthcare workers who are at most risk and vulnerable to get infected by the virus. While India has sound vaccine manufacturing capacity at its disposal, what is really needed is a comprehensive and multi-pronged mass education strategy to achieve the last mile delivery. We need to use our research and study findings in varied ways and smart data analytics to bust rumours, myths and hesitancy among the population on getting inoculated. Evidences are the best means to spread awareness and help authentic information reach each and every citizen of India. We have to stop the virus in its transit corridors, ramp up all efforts to protect both life and livelihood.”
The vaccine efficacy is generally reported as Relative Risk Reduction (RRR). The studies have already demonstrated that being vaccinated against Covid-19 significantly reduces the risk of being infected. For example, in clinical trials, a 95 per cent vaccine efficacy would indicate vaccinated individuals will be 95 per cent less likely to get Covid-19. If 1 per cent of the unvaccinated population develops Covid-19, getting the vaccine would reduce the chances of getting Covid-19 by 95 per cent, resulting in a 0.05 per cent infection rate.
With 14 days of follow up After second dose, incidence of infection was 1.6%, says PGI Study
Professor PVM Lakshmi, from the Department of Community Medicine and School of Public Health, PGI, along with two other doctors from the institute, documented the data regarding breakthrough infections in a group of healthcare workers at the institute, who had received the Covid-19 vaccine. The report was published in the New England Journal of Medicine this month.
As per the data in the report, among 12,248 healthcare workers, 7,170 (58.5 per cent) had received the first dose of the Covid-19 vaccine and 3,650 (29.8 per cent) had received the second dose as per the central government’s guidelines. Meanwhile, at least 5,078 healthcare workers (41.5 per cent) were unvaccinated.
Since the start of the vaccination programme, at least 506 healthcare workers have tested positive for SARS-CoV-2. Out of the 7,170 who had received the first dose of the vaccine, 184 (2.6 per cent) healthcare workers tested positive; the median time between the receipt of the first dose and the positive test was 44 days. A total of 72 of 3,650 healthcare workers (2 per cent) tested positive after the second dose; the median time from receipt of the second dose to the positive test was 20 days.
Among the healthcare workers who received both the doses and completed at least 14 days of follow-up after the second dose, the incidence of breakthrough infection was 1.6 per cent (48 of 3,000 healthcare workers); the median time from receipt of the second dose to breakthrough infection was 29.5 days.
“This was a preliminary study done in April, when the mutant strains were not floating, and now that more than 70-75 per cent healthcare workers have been vaccinated, there needs to be another study and analysis to understand the changes in the period of time and the accumulating evidence must be reviewed. More medical institutes and hospitals must do periodical studies related to infections and vaccinations. At present, Punjab, as a state, is looking at vaccination data to understand more,” says Professor Lakshmi.