Risk of COVID among fully vaccinated healthcare workers significantly lower compared to unvaccinated HCWs, finds study

A fresh study from Christian Medical College, Vellore on vaccinated healthcare workers suggests that the risk of infection among fully vaccinated HCWs was significantly lower when compared with unvaccinated HCWs.

The data of this study as shared by the researchers states that two doses of Covishield gave the said HCWs 65 per cent protection against infection, 77 per cent against hospitalisation, 92 per cent against the need for oxygen treatment and 94 per cent against the need for ICU care.

The paper states "the only staff member who died since the beginning of the pandemic had multiple co-morbidities and had not taken the vaccine".

"Out of 10,600 employees in CMC, 8991 staff (84.8 per cent) got the jab between January 21, 2021, and April 30, 2021. A majority (93.4 per cent) received Covishield, and the remainder, Covaxin," said the research team.

The vaccination with two doses reduced hospitalisation need for oxygen therapy and ICU admission. The protective effect of vaccination in preventing infection, hospitalization, need for oxygen and ICU admission were 65 per cent, 77 per cent, 92 per cent and 94 per cent respectively.

Within the period of February 21 to May 19, approximately 1350 staffs were tested positive on RT-PCR, the median (interquartile range) age was 33 years (27-41) whose female/male ratio was 3:2.

The median time from the first dose to the development of infection was 77 (62-89) days which coincided with the second peak in India during April and May 2021.

33 HCWs developed infection within two weeks of the second dose of vaccine. Among fully vaccinated HCWs 679 (9.6 per cent) developed infection 47 days (34-58) after the second dose. The risk of infection among fully vaccinated HCWs was significantly lower when compared with unvaccinated HCWs.

However, "subgroup analysis on the efficacy of the two vaccines was not possible due to few HCWs receiving Covaxin."

They mentioned that "some HCWs (17 per cent) could not take the second dose, initially due to vaccine shortage and subsequently despite vaccine availability, due to changes in guidelines on the interval between doses."