Effect of vaccine type, prior COVID-19 infection on symptoms, antibodies after HCW vaccination

Editor's Note

This study by Johns Hopkins researchers finds that regardless of vaccine reaction or prior COVID-19 infection, both mRNA vaccines provide a robust antibody response in healthcare workers (HCWs).

Questionnaires and serum samples were collected from 954 HCWs at 14 or more days after their second doses of either the Moderna or Pfizer vaccines. Clinically significant symptoms were reported by 52 (5%) HCWs after dose 1 and 407 (43%) after dose 2. After adjusting for prior COVID-19 infection, age, and gender, the odds of clinically significant symptoms after either dose were higher with the Moderna vaccine.

Regardless of symptoms, 953 (99.9%) HCWs developed antibodies at 14 or more days after dose 2. One HCW who was taking immunosuppressant medication did not develop antibodies. HCW characteristics that were independently associated with higher median antibody levels, after adjusting for time after dose 2 included those who:

• reported clinically significant symptoms
• were younger than 60 years of age
• were female gender
• received the Moderna vaccine
• had prior COVID-19 infection.

The role of higher antibody levels in preventing COVID-19 and providing lasting immunity remains unknown, the researchers say.