Do vaccines work against omicrons? see what is known

Initial studies carried out in different laboratories suggest that two doses of the Covid vaccine are insufficient to stop omicron, a new variant of the coronavirus. On the other hand, the analyzes also show that the application of a third dose restores good levels of protection.

The research, however, is still preliminary, as the omicron has been in circulation for a few weeks. For this reason, researchers emphasize that more evidence is needed to confirm the strength of the third dose against the new strain, the same caution adopted by the WHO (World Health Organization).

See what is known, so far, about the effectiveness of vaccines in relation to the omicron variant.

I took two doses of Covid vaccine (or a single dose of Janssen). Am I protected against omicron?

Probably not, according to preliminary analysis — which raises the fear that there may be an increase in the number of infected in countries, even among those immunized with up to two doses or who had Covid.

In a laboratory test, the Pfizer and BioNTech vaccine showed a loss in the rate of neutralizing antibodies against the new strain. However, according to the companies, it is believed that two doses still prevent serious conditions.

A survey conducted by a South African health care provider indicated that people immunized with two doses of Pfizer/BioNTech and who were infected with omicron have a 70% chance of not needing hospitalization, below the percentage compared to those infected with delta.

In addition, protection against infection by the new strain dropped from 80% to 33%. The work was based on 211,000 Covid tests, of which 78 thousand were attributed to omicron, considering the prevalence of the strain in the period analyzed.

The drop in protection was also observed by Oxford University researchers who analyzed blood samples from those immunized with both the Pfizer/BioNTech and AstraZeneca product.

The picture was repeated in an analysis of researchers in the United States. They examined blood from people who had received two doses of Moderna or Pfizer/BioNTech and one from Janssen.

Analyzes in South Africa and Israel also signaled loss of effectiveness with two doses of Pfizer.

All these tests, which have not been reviewed by other experts and should be viewed with caution, converge to the result that the application of the third dose can restore protection against the disease.

Although more information is still needed on the effectiveness of vaccines in combating omicron, laboratories announced that they intend to update versions against the new strain, to be delivered in 2022.

I’ve already had the Covid booster shot. Am I protected against omicron?

It is assumed that yes, according to preliminary data.

Initial results from a UK analysis of 581 people infected with the omicron suggested that a third dose of Pfizer offers 70% to 75% protection against the new strain.

Another study, conducted in Israel, also indicated greater protection against omicron with the third dose, but at a lower level than that achieved in relation to delta.

The WHO, however, adopts a cautious speech and says more evidence is needed that the third dose actually works against omicrons.

A South African research, for example, suggested that even three doses would not be able to prevent the contamination by the new strain.

Anyway, in Brazil, before the emergence of the variant, it was already decided that all people over 18 years old can receive the booster five months after the second dose.

In São Paulo, the interval between the second and third dose is four months.

In the case of Janssen’s vaccine, the booster has been applied in the country after two months or more of the initial single dose.

With only one dose of vaccine from Pfizer, Astrazeneca or Coronavac am I protected against omicron?

It is not, neither against omicron nor against the other variants of Sars-Cov-2.

The laboratories that developed the immunizing agents recommend the application of at least two doses so that they have the expected effect: avoiding hospitalizations and deaths.

What does WHO say about the new variant?

The entity considers that omicron represents a very high risk. It is feared that it will spread faster than the delta variant, infecting more people and straining health systems.

In South Africa, for example, the number of new daily infections soared after the identification of the new strain in the country. In addition, there are reports of cases of reinfection.

In the assessment of the WHO, there is a series of uncertainties about the new strain, which, until this Tuesday (14), had confirmed cases in 77 countries, including Brazil.

Why does the micron ‘dribble’ the vaccine?

Vaccines are developed based on the genetic sequence of the coronavirus. Thus, if a new strain with mutations differs significantly from previous variants, there is a chance that it will escape the body’s defenses.

Researchers at the Bambino Gesù hospital, in Rome, Italy, concluded that the micron has 43 mutations in the S protein (spike or spike), used by Sars-Cov-2 to enter human cells.

Immunizers from Pfizer, AstraZeneca and Janssen, for example, target this protein to teach the human body to fight the disease.

In the case of Coronavac, which is based on inactivated virus technology, the product teaches the immune system to fight the entire coronavirus, not just the spike protein. Thus, it is possible that your protection will be maintained against the new variant.

However, in all cases, further studies are needed to confirm this.

Does the omicron cause serious pictures of Covid?

There is no evidence to demonstrate this, as yet.

Most cases in Europe, according to WHO, have mild symptoms. Others who are infected are asymptomatic.

A similar scenario has been seen in South Africa, where there are more admissions of patients with Covid, but with no impact on the number of deaths — in the country, less than half of the population has been fully vaccinated.

For now, the only death related to the new strain that is known occurred in the United Kingdom. In the country, confirmed cases of omicrons exceed 4,000.

Does the booster dose cause side effects?

Yes, it can, as well as the first and second doses. However, they are generally lightweight and pose no danger, experts say.

The most common reactions repeat those seen after immunization with the first and second doses: pain at the injection site, myalgia (pain in the body), tiredness, headache, fever, chills and swelling at the injection site.

Other less frequent side effects are nausea, vomiting, diarrhea, bruises and redness on the arm, high fever, excessive sweating and itchy skin.