Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in December 2019 has caused tremendous panic around the globe for the past one and half year. During a health crisis wherein the scientific community are trying to contain the effects of the first wave of coronavirus disease-19 (COVID-19), the world was recently struck by a second wave.1 As of 20th June, 2021 more than 178 million individuals were infected with SARS-CoV-2 and 3.86 million SARS-CoV-2-associated deaths were reported.2 USA, India and Brazil account for most of the cases worldwide with India recording about 29.88 million cases and 3.86 million deaths.2,3
To tackle the ongoing pandemic, the Government of India initiated the world’s largest vaccination drive since 16th January 2021 in a phased manner with healthcare workers (HCWs) getting inoculated initially with either of the two vaccines named BBV-152 (COVAXIN®) and AZD1222 (COVISHIELDTM) after the requisite approval for emergency use in the country. The vaccination of frontline workers (FLWs) was initiated on 2nd February. Subsequently, the Gam-COVID-Vac (Sputnik V) got approval and was launched in India on 14th May 2021.4,5 India has administered 245.9 million citizens with at least a single dose of either BBV-152 or AZD1222 vaccine and among them, 52.1 million people got both the dosages (complete vaccination) and Odisha has vaccinated 9 million citizens with at least a single dose of either BBV-152 or AZD1222 vaccine and among them, 1.9 million people got both the dosages (complete vaccination) as of mid-June.6
During the early stages of the pandemic, scientists hypothesized that SARS-CoV-2 transmission would be slowed by herd immunity resulting from spontaneous infection, vaccination, or both.7 Although several studies have demonstrated that SARS-CoV-2 infection in vaccinated individuals present clinically mild symptoms, it is critical to determine whether severe symptoms can arise in others despite vaccination, as development of variants is a continuous process.8 A vaccine breakthrough infection is defined as the detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person ≥14 days after receipt of all recommended doses of an approved COVID-19 vaccine.9
In the present study, we attempted to record the breakthrough cases reported through passive and voluntary reporting at various healthcare facilities from different districts of Odisha, their clinical presentation, requirement of hospitalization post infection and antibody titer against spike antigen.