The efficacy of three COVID-19 vaccinations was compared by a team of experts at Massachusetts General Hospital (MGH). Their research, which was published in the Journal of Infectious Diseases, also looked at data from previous trials to see how effectively each vaccination protects against coronavirus. They compared the injections made by Moderna, Pfizer, and Johnson & Johnson.
Although the three vaccines have different doses and delivery mechanisms, they all target the “spike” protein on the SARS-CoV-2 strain of COVID-19.
“We wanted to know how much anti-spike antibody people develop after they take each vaccination,” said senior author Dr. John Iafrate.
His team did it by analysing blood samples from 215 healthy persons in the United States.
At least one week prior, everyone of them had received one or two doses of vaccination.
The researchers also analyzed blood samples from a group of adults who were unvaccinated and not infected with COVID-19, and another group of adults who were unvaccinated and recovering from infections.
Their results found that two doses of the Moderna and Pfizer vaccines produced roughly similar concentrations of antibodies, which were greater than 100-fold higher than the amount produced by the single-dose Johnson & Johnson vaccine.
The study also found that people who had recovered from COVID-19 infections had antibody concentrations similar to those who had received a single dose of Moderna and Pfizer.
But a separate analysis showed that the Johnson & Johnson vaccine was somewhat more effective at stimulating the production of a different type of immune cell, known as CD4 T cells.
They also examined the vaccines’ ability to neutralise three variants of the virus, known by the names Beta, Delta and Gamma.
