A Belgium study compared the levels of antibodies in healthcare workers after receiving either the Pfizer/BioNTech or Moderna vaccines and found that the healthcare workers that received the Moderna COVID-19 vaccine had a higher antibody response than the healthcare workers that received the Pfizer/BioNTech COVID-19 vaccine.

The study looked at antibody levels six to ten weeks after receiving the second dose of each COVID-19 vaccine in a total of 1647 healthcare workers. The study found that those vaccinated with the Moderna COVID-19 vaccine produced higher levels of antibodies to the SARS-CoV-2 spike protein (2881 U/ml) compared to those vaccinated with the Pfizer/BioNTech BNT126b2 COVID-19 vaccine (1108 U/ml).

The study also looked at antibody titers in those healthcare workers that had previously been infected with the SARS-CoV-2 virus and found those who had a higher antibody titer after vaccination as well, with those receiving the Moderna COVID vaccine having an average antibody titer of 10708 U/ml and those receiving the Pfizer/BioNTech COVID-19 vaccine demonstrating an antibody titer of 8174 U/ml.

The Moderna COVID-19 vaccine may provide a greater antibody response because of its higher dose of the SARS-CoV-2 spike protein mRNA (messenger RNA) (100 micrograms vs 30 micrograms in the Pfizer/BioNTech COVID-19 vaccine as well as the longer time between the first and second dose (4 weeks for Moderna and 3 weeks for the Pfizer/BioNTech vaccine).

This study did have limitations, which included that it only included healthcare workers and did not discuss the timing of prior COVID-19 infections, which could have also impacted antibody titer levels if it had been longer since infection.

The study does suggest the benefit of vaccination after COVID-19 infection, with a higher antibody titer level, which may provide more protection against future COVID-19 infections.

Curious about what the COVID-19 vaccines are made of? Read our article about what’s in the COVID-19 mRNA vaccines here.