The immunity conferred by the vaccination against Covid-19 can begin 12 to 15 days after the injection, it happens that people who have already received a first dose of vaccine are still infected with the virus. What to do when you contract Covid-19 after a first injection of a vaccine? Discover the recommendations of the Vaccine Strategy Orientation Council (COSV) on the issue.
What are the differences in effectiveness for one or two doses of vaccine?
While vaccines reduce the risk two weeks after a first injection, many studies have shown that they are much more effective after a second dose is injected. For example, the Pfizer vaccine makes it possible in 79% of cases to develop antibodies after having received a single dose. But these figures go down to 50% for the Alpha variant (initially appeared in England), to 32% for the Delta variant (first discovered in India) and to 25% for the Beta variant (initially observed in South Africa).
However, a single dose of vaccine still makes it possible to limit the severe forms of the disease since, according to a study by Public Health England, the Pfizer vaccine would be 83% effective in preventing severe forms of the Alpha variant after a first injection. against 95% with two doses and 94% for the Delta variant against 96% with two doses.
What to do if you contract Covid-19 after a first injection of a vaccine?
Although both doses of a Covid-19 vaccine (except that from Janssen which requires only one injection) are necessary to develop a significant level of immunity, it is agreed that a person who has previously been infected with Covid-19, only needs a single dose to create a level of immunity similar to a conventional vaccination schedule. But what about people who contract Covid-19 after a first injection? To see more clearly, the Orientation Council of the vaccine strategy (COSV) published an opinion on the subject on June 18. The recommendations differ according to two types of situation:
- For SARS-CoV-2 infection occurring less than 15 days after the injection of a first dose of vaccine, the COSV recommends injecting a second dose of vaccine, starting two months later. the infection. According to experts, the immunity induced after a dose of vaccine and infection with the virus within 15 days of each other is not equivalent to the immunity induced by a full vaccination.
- For SARS-CoV-2 infection occurring more than 15 days after the injection of a first dose of vaccine, it is not necessary to obtain a second dose of vaccine. And for good reason, the specialists consider that the infection represents a stimulation equivalent to the injection of a second dose of vaccine, with a sufficient delay.
The opinion of the Vaccine Strategy Orientation Council also specifies that these recommendations apply ” for all the vaccines currently authorized in France, insofar as the kinetics of the appearance of protective immunity for all these vaccines are relatively comparable “.
