MAINTENANCE. “In case of infection with Omicron, without vaccination, protection is not enough”

“I got all my vaccines.” The last (recall) was December 1, 2021. On December 10, I tested positive for Covid-19. Should I consider this a fourth dose? »asked François.

Efficacy, according to the latest recommendations of the Ministry of Health, an infection or Covid-19 equal to the injection of the vaccine. However, it all depends on when you became infected: more than three months after your recall, or less than three months.

“If the infection occurred more than three months after the first recall, a second recall is not necessary. In fact, an infectious episode causes an immune response or less equivalent to the cell of a booster vaccine. ‘lighting on the website of the Ministry of Health.

Et “If the infection occurred less than 3 months after the first recall, a second recall is required. It is appropriate to wait at least 3 months after infection for people aged 80 and over, residents in Ehpad and USLD or 6 months after infection for people aged 60 to 79 years before the second vaccination booster..

In your case, François, your infection is not equivalent to a new dose of vaccine because it occurred too soon after the injection of your vaccine booster, ie ten days later.

Also read: Covid19. Is the fourth dose mandatory? We answer you

To go further and understand that an infection is equivalent to a dose of vaccine, we asked Yannick Simonin, a virologist and research professor at the University of Montpellier. Maintenance.

Often antibodies against Spike

What happens in the body during a vaccine injection or infection?

When vaccinated or infected with Covid-19, the first response is a humoral response. The body then produced antibodies in a few days to block the virus from entering. Then several weeks later, there is the immune response which is a memory response. The cells prepare to react again in case of infection.

In cases of Covid-19, RNA vaccines are effective machines stimulate two types of responses. There are vaccines that only stimulate the humoral response, for example, inactivated vaccines, and probably Sinovac vaccine. But in most cases, in Europe, with the vaccines used, we have this double incentive.

What about the quality of the immune response, either in case of infection or in case of vaccination?

There are actually different immune responses. With vaccination, the antibodies are directed to the Spike protein, when with a Covid infection, the body develops antibodies that will have other du virus proteins.

With vaccination, the antibodies developed are more numerous and more effective against Spike, following an infection, the antibodies also go against other fragments of the virus, which can be assimilated to a dilution of the immune system. It doesn’t just fight Spike protein.

Also read: Covid19. I was infected after my third dose, am I well protected?

Cu Omicron, just being infected but not vaccinated, protection is not enough.

– Yannick Simonin

In which case do you benefit from the best protection?

With Omicron, the data suggest that it is better protected after vaccination after infection. It is often better protected against an infection, but with this vaccination it would be more effective.

The best protection is vaccination, two doses, following an infection. There the antibodies are more important and more stable over time. Two doses of the vaccine reduce the intensity of the symptoms.

Two or three doses, followed by infection, is the best stimulant. Cu Omicron, just being infected, but not vaccinated, is not enough protection.

Also read: Covid19. Incubation, contagion, symptoms: do not change Omicron variants?

How many months protected?

So is that in line with the Ministry of Health’s immunization recommendations? The ministry explains that the infection can replace a booster vaccine in some cases.

Yes, that’s right. However, only one infected person has not been vaccinated, the dose of the vaccine cannot be taken into account.

Where is the knowledge about the duration of protection provided by vaccines?

Protection against symptomatic forms is estimated at 4-5 months after vaccine dose, after which it becomes weaker, more protection against severe forms is always there, at about 80%.

Hence a fourth dose for those over 60 and which allows to increase the levels of protection. There may be an incentive for a booster dose in the general population in the fall of September, but it will depend on the variants that are circulating at that time.

Also read: Covid19. A clear decline in cases observed in France: what should we expect for this summer?

We are moving towards a period of calm in the coming months. We have a basin of immune responses in the population: people completely vaccinated, those vaccinated then infected, those who were infected with different variants …

MAINTENANCE. “In case of Omicron infection, without vaccination, protection is not enough”

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