Data from a real-world study that evaluated Janssen’s vaccine against Covid-19 show that the immunizing agent had a 73.6% effectiveness rate. The results were published this Tuesday (2) in the JAMA Network Open magazine.
Unlike efficacy tests, which concern studies conducted in controlled environments, such as those carried out during vaccine development, effectiveness data reflect the results of vaccination in practice in large populations.
The study evaluated patients in the Mayo Clinic’s healthcare system between February and July this year. The researchers followed nearly 9,000 patients vaccinated with Janssen and nearly 89,000 people who were not immunized. The research focused on evaluating how many individuals tested positive for Covid-19.
Among the 8,889 vaccinated patients, 60 had a positive molecular diagnostic test (PCR). Among 88,898 unvaccinated patients, 2,236 tested positive for the disease.
The researchers concluded that the vaccine was 73.6% effective and led to a 3.73-fold reduction in coronavirus infections. The finding is similar to data from clinical trials that found the vaccine to be 66.9% effective against moderate to severe Covid-19.
The new research showed a reduction in severe cases, especially hospitalizations, but too few people took Covid-19 among the vaccinated group to draw a consistent conclusion about how effectively the vaccine prevented deaths.
In a supplementary commentary, researcher Mohammad Sajadi of the Institute of Human Virology at the University of Maryland School of Medicine in the United States argued that the findings are part of a growing body of work that suggests “room for improvement” with the vaccine from Janssen.
“What is becoming clearer over time is that the single-dose vaccine regimen [da Janssen] appears to be inferior to mRNA vaccines in terms of [eficácia da vacina]”, wrote Sajadi, comparing the Janssen vaccine to a different type of vaccine against Covid-19, such as those from Pfizer and Moderna.
Sajadi noted that the same group of researchers who conducted this latest Janssen study had previously looked at the effectiveness of the Pfizer and Moderna vaccines, which had “significantly greater” effectiveness. In that study, the real-world effectiveness of the Pfizer vaccine was 86.1%. For Modern it was 93.3%.
In September, a comparative study of all three vaccines revealed that Moderna’s vaccine is slightly more effective than Pfizer’s in real-life use in terms of hospitalizations.
Moderna’s vaccine provided 93% protection against hospitalization and Pfizer’s was 88% effective. Sajadi said Janssen’s vaccine improvement could come in a second dose or a booster of a messenger RNA (mRNA) vaccine against Covid-19.
This is a translated text. To read the original in English, click here.
Reference: CNN Brasil
