The Johnson & Johnson COVID-19 vaccine may be less effective against the Delta variant of the virus compared to the vaccine based on the mRNA technology, according to the latest study, cited by the US online newspaper “USA Today News”.
The study indicates that people who receive the Johnson & Johnson vaccine may need a second dose, preferably from Pfizer or Moderna.
While the study has not yet been reviewed or published, its findings are consistent with AstraZeneca's study, which found that one dose of the vaccine is in 33 percent effective against the symptomatic disease caused by the Delta variant and 60 percent effective against this variant after the second dose, USA Today News reported.
“The message we wanted to convey is not that people should not get the J & J vaccine, but instead we hope that in the future it will either be strengthened with another dose of J & J, or the Pfizer or Moderna vaccines” Nathaniel Landau, virologist at the Grossman New York University School of Medicine, who led the study said.
These results contradict research published by the Johnson & Johnson company that state that a single dose of their vaccine is effective against the more virulent and infectious Delta variant of COVID-19, USA Today News noted.
This variant is still spreading in the US and accounts for about 83 percent of infections, according to data from the Centers for Disease Control and Prevention (CDC). No vaccine against COVID-19 is 100 percent effective, which is shown by the increase in cases of vaccinated people. What vaccines proved is that they protect people against a serious course of the disease.