Faced with the Delta variant, non-vaccinated people who have had Covid in the past are said to be better protected than people who have been only vaccinated. This is what a study issued this Wednesday January 19, 2022, and carried out by U.S. health authorities, shows.
In New-York and California, the U.S. health authorities assessed Covid cases from late May to November 2021 – while the Delta variant was prevailing in the U.S. Yet, please note that since the study has been carried out, the Omicron variant has broken out in the United States until it prevailed, and the vaccination campaign for the third dose has been launched; results of a new study could be different depending on the period assessed.
And yet, the study published this Wednesday shows people vaccinated but never infected are 6 times less likely to catch Covid in California and about 5 times less likely in New-York than non-vaccinated and never infected people.
But the risk is even lower for people who had prior infection and not vaccinated: 29-fold in California and 15 in New York. Prior to the outbreak of Delta, it was the very contrary: vaccinees who never had Covid before were better protected than non-vaccinated people already infected.
Before or after the outbreak of Delta in the U.S., people the less protected are and will be those how have never been vaccinated or infected in the past.
“This might be due to differential stimulation of the immune response” caused whether by the real virus or a vaccine, the U.S. health authorities explain. This change of trend also coincided “with early declining of vaccine-induced immunity in many persons” prior to booster. According to the American health authorities, this study agrees with other studies carried out in other countries that “also demonstrated increased protection in persons with previous infection, with or without vaccination, relative to vaccination alone”.
Nevertheless, “vaccination remains the safest and primary strategy”, they say, the vaccine enabling to prevent severe complications.
