The COVID 19 infection is highly transmissible and spreading globally, including in populations with high vaccination rates. COVID-19 vaccination in India, was started in month of January 2021 with healthcare workers (HCWs) becoming the first to get vaccinated. However, there has been lot debate on the efficacy of the vaccine. This study highlights breakthrough COVID-19 infections among vaccinated HCWs comparing clinical and lab parameter among hospitalized and non hospitalized.MATERIALThis was a retrospective study conducted using questionnaire assessing COVID-19 like symptoms and confirmed COVID 19 infections among fully vaccinated HCWs (all faculty including nurses, wardboys, professors, post graduate students and interns) of the institute from a period of 4 months from March 2021 to June 2021. The number of infections was also matched with hospital records.OBSERVATIONOut of 36 HCWs, all had received both doses of covishield vaccine. Males were 18 and females were 18, mean age was found to ne 32.17. People with co-morbidities were 13.9% including diabetes and hypertension. Out 36 HCWs, 4 people required hospitalization ie 11%, all other cases had mild symptoms and none required oxygen support. There was no significant difference between hospitalized and non-hospitalized with regard to routine lab parameters, but there significant elevation of inflammatory marker -CRP being positive in 2 hospitalized cases, with p value being significant (p<0.001).CONCLUSIONThis study identifies that breakthrough infections among vaccinated HCWs(health care workers) were common. Most breakthrough infections were mild or asymptomatic, although persistent symptoms did occur. The findings suggested that COVID-19 were more severe in hospitalized patients compared to non-hospitalized and even though infections did occur none resulted in any severe form or mortality, it also indicates that vaccination prevents from severe form of the disease. But, preventive measures should be continued even among vaccinated individuals.