New research on the effectiveness of vaccination in opposition to COVID-19
A 3rd dose of COVID-19 vaccine provided no extra safety to healthcare employees who had been contaminated with the Omicron variant after which acquired two doses of a messenger RNA vaccine, a research discovered. collaborated with many Quebec researchers.
This “hybrid safety” appeared to guard these employees in opposition to reinfection with Omicron and its subvariants for an prolonged time period, the researchers write within the pages of the medical journal The Lancet: Infectious Ailments.
“Vaccination with a earlier an infection provides superb safety,” summarized the research’s lead writer, Dr. Sara Carazo of the Nationwide Institute of Public Well being of Quebec.
If this safety persists within the face of future variants, the authors add, future doses of the vaccine could also be of solely restricted use for individuals who have such hybrid immunity.
The research centered on all well being employees (medical doctors, nurses, pharmacists and others) aged 18 and over who work within the public community of Quebec. Researchers in contrast contributors who examined constructive for coronavirus in the course of the research interval to those that examined detrimental.
They then appeared on the vaccination standing of the contributors after which decided what number of of them had been reinfected with the BA.2 variant after an preliminary an infection with the BA.1 variant (Omicron).
About 3% of contaminated contributors had an preliminary an infection and two doses of vaccine, and about 4% had an preliminary an infection and three doses of vaccine.
Amongst topics contaminated with the Omicron variant earlier than receiving two doses of messenger RNA vaccine, the danger of reinfection with BA.2 was diminished by 96%, and the danger of symptomatic reinfection by 98%. Including a 3rd dose of vaccine didn’t enhance this safety, which lasted at the very least 5 months after the first an infection.
“Omicron utterly modified the image,” mentioned Dr. Carazo. The proportion of the inhabitants contaminated with Omicron was so giant that the protecting impact of this an infection turns into crucial for public well being.”
Vaccination continues to be the perfect weapon we’ve got in opposition to the virus, she added, particularly for individuals who haven’t had a earlier an infection or whose earlier an infection occurred earlier than the arrival of the virus. Omicron variant.
The research authors level out that their work centered on healthcare employees aged 18 and older; it will due to this fact be tough to extrapolate their outcomes for kids, the aged or immunosuppressed people.
Equally, it isn’t recognized with certainty whether or not the safety famous within the face of reinfection by the BA.2 variant would persist within the face of recent variants, comparable to BA.4 and BA.5. Preliminary research in Portugal and Qatar conclude, nevertheless, that the hybrid safety conferred by BA.1 an infection and vaccination stays excessive, at between 76% and 80%.
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