Previous research has shown that so-called hybrid immunity, when you have both received a vaccine and undergone an infection, produces more antibodies against new covid-19 viruses. Now new findings show that it may be the other way around, at least for some.
It is the so-called Community study, a collaboration between Danderyd Hospital and Karolinska Institutet, among others, which shows that those who have not had covid-19 before but are triple vaccinated, get more antibodies if they are infected with omicron.
– We have compared two groups, partly those who are triple vaccinated and have had covid-19, partly those who are triple vaccinated but have not had covid-19, says chief physician Sebastian Havervall who is a doctoral student in the Community study.
All in both groups have since received omicrons.
Stronger antibody response
– What is a little surprising is that the latter group, ie those who were vaccinated but had not had covid-19 before, received a stronger antibody response, he says.
This goes against previous studies. They have shown that it is an advantage to be both vaccinated and have had covid. This type of hybrid immunity has been considered to provide better protection against new infections.
– Here it was the other way around, that the combination of previous infection and vaccine gave a weaker immune response than just vaccine in those who became infected with omicron, says Charlotte Thålin, chief physician and responsible researcher for the Community study.
Can avoid refill dose
However, it is too early to conclude that those who have received three injections, but have not had the infection, have better protection against becoming infected with a new infection. But if the result stands, it may mean that some people may not need a fourth syringe or that you can show who really needs refill doses.
– This is something we must look at now. It can also be the case that you get different high immune responses depending on which variant of the virus you have become ill from or what type of vaccine you have received. We also do not know what the immune response will look like after new virus variants and new vaccines, says Sebastian Havervall.