Background: Coronavirus Disease 2019 (COVID-19), emerged in China at the end of 2019, became a major threat to health around the world. Breakthrough infection following COVID-19 vaccine has clinical and public health significance. The highest groups at risk of infection during the COVID-19 pandemic is health care workers; the physicians are the frontline workers. This study aimed to assess the prevalence of breakthrough COVID-19 infection and their clinical presentation, co-morbidities and outcome among physicians who were fully vaccinated, working in COVID-19 treatment centers in Myanmar.

Methods: A cross-sectional descriptive study was conducted among physicians, at least 14 days after receiving second dose, working at COVID-19 treatment centers in Myanmar, during the third wave from end of May to August 2021. Data were collected by using standardized forms and analysis was done.

Results: Among 410 physicians, 98.2% (221/225) received two dose of vaccination: Covaxin 90.0%, Covishield 9.5% and Sputink V 0.5%. They received first dose of vaccine in January/February 2021 and second dose in March/April 2021. In Myanmar, third wave started in end of May; the largest pandemic surge had reached its peak in July, 2021. In the third wave, most of them 72.9% (161/221) did not experience no infection. The prevalence of fully vaccinated break through infection was 27.1% (60/221); the majority 78.3% (47/60) were mild symptomatic infection. Severe infection was seen in 10% of physicians with breakthrough infection who required hospital admission and oxygen therapy. The common presenting symptoms in order of frequency were body aches and pain 62.6%, sneezing 56.6%, headache 53.5%, cough 52.5%, sore throat 45.5%, anosmia 33.3%, runny nose 23.2% and loose motion 27.3%. The uncommon symptoms were dyspnoea 9.1%, vertigo 6.1%, skin rash 5.1%, vomiting 5.1%, petechiae 3.0%, tinnitus 3.0% and silent hypoxia 3.0%, and non-per-os 1%. Most of them did not have any significant comorbidities. One out of six physicians having severe infection had diabetes mellitus and two were obese. The mean duration of hospital stay was 7 days. None of the cases was fatal.

Conclusions: In this study, over 98% of physicians were fully vaccinated; majority with Covaxin. One in four physicians had breakthrough infection in third wave; mainly mild form. Nearly half of them had possible delta symptoms; aches and pain, sneezing, runny nose, headache, cough, and sore throat. Awareness of rare but important symptoms like Non-per-Os and vertigo should be highlighted both to public and health care personnel. Ten percent of physicians with breakthrough infection were severe. Mortality rate was zero.