With covid infections forecast to rise again in the coming months, Spain will begin offering booster doses of coronavirus vaccines from September 26. But the diversity of existing vaccines, the unpredictability of the coronavirus, and the wide variety of personal situations confuse many citizens, who question whether a booster dose is right for them, with which vaccine and when they should get it.
To clarify these doubts, The vanguard reviewed published data on available vaccines, as well as recommendations from the Public Health Commission of the Ministry of Health and the European Center for Disease Prevention and Control (ECDC), and consulted infectious disease and public health specialists.
FOR VULNERABLE GROUPS
Whether you get a booster dose depends on what you want to achieve with it. If the goal is to prevent covid from causing serious complications, “a booster dose with any of the vaccines currently available offers very high protection,” said Roger Paredes, head of the infectious disease service at Can Ruti hospital and researcher. of the Irsi Caixa institute.
In Spain, the Public Health Commission recommends that people in the highest risk groups of suffering from severe complications from covid receive a booster dose this fall: people over the age of 60, people living in nursing homes and people with diseases or situations that make them more vulnerable to covid.
The conditions considered to be at greatest risk are: immunodeficiencies, tumors, having received a transplant, being on dialysis and having Down syndrome and being over 40 years of age.
The first people to receive booster doses will be over 80 and interns in residence, according to the priorities established by the Public Health Commission. Then the health and social health personnel will arrive. Finally, people aged 60 to 79 and those with at-risk conditions.
They will be offered new vaccines from Pfizer and Moderna that immunize against both the original variant of the coronavirus and the BA.1 variant of omicron.
If a person has recently had covid, they can wait until five months have passed since the infection because “the protection that is acquired in this period is high”, reports Magda Campins, epidemiologist at Vall d’Hebron hospital and president of the institute. scientific committee of the covid of Catalonia. “But there is no contraindication to receiving a booster dose before five months have passed.”
FOR THOSE WHO HAVE DONE WITH VULNERABLE PEOPLE
If the goal is to avoid being infected, which is convenient for those who work or live with vulnerable people, none of the vaccines offer neither very high nor very long-lasting protection, reports Roger Paredes. Nonetheless, the Spanish vaccination strategy plans to offer booster doses to health and social health personnel.
The reason vaccines are highly protective against serious complications and low against contagion is that these two types of protection rely on different parts of the immune system. Protection against serious complications is largely achieved by immune cells, while protection against infection depends primarily on neutralizing antibodies.
The amount of neutralizing antibodies increases rapidly after vaccination or after infection, but decreases in the following months, reports Antoni Trilla, epidemiologist at the Hospital Clínic. This explains why a person who has been vaccinated can become infected a few months later, although they will likely have a mild infection thanks to cellular immunity.
Also, as the coronavirus evolves, it changes the proteins that the antibodies recognize. For this reason, adds Antoni Trilla, the antibodies a person acquires against one variant are somewhat less effective against subsequent variants. This is why Pfizer-BioNTeech and Moderna developed vaccines against the BA.1 variants of omicron which were dominant at the beginning of the year and against the BA.5 variant which is dominant now.
These omicron-adapted vaccines are expected to be more effective than their predecessors in preventing infections. But “they aren’t much more effective,” warns Magda Campins. “People who are given booster doses adapted for omicron will also be at risk of infection and should continue to wear a mask and take precautions when dealing with vulnerable people.”
FOR THE REST OF THE HEALTHY ADULT POPULATION
In Spain, a fourth dose is not recommended for healthy people under the age of 60. The reason is that an additional dose will barely protect them from the serious complications of covid, as with three doses they already have very high protection. And it won’t protect them much from contagion either.
It is recommended that the entire adult population complete the vaccination schedule with three doses, as it has been shown to offer significantly greater protection than two or fewer doses against serious complications in young adults.
All the specialists consulted for this article are in favor of booster doses being available to anyone who wants them. They defend that those who care for the elderly or the sick should have the opportunity to be vaccinated to reduce the risk of infecting them even if they are not health or social health workers.
Furthermore, they advocate that people with heart disease, diabetes, obesity or lung disease, who are not as high a risk as other more vulnerable groups but not as low as the healthy adult population, can have access to booster doses. In Spain, the Ministry of Health does not foresee for now that these groups can be vaccinated.
FOR CHILDREN AND BOYS
Spain did not approve of offering third doses to children and adolescents, as it did for the adult population, recalls Quique Bassat, a pediatrician and epidemiologist at the Barcelona Institute for Global Health (ISGlobal). Nor is it planned to offer them a booster dose now in the fall.
But it’s convenient for them to complete the full vaccination schedule with two doses if they haven’t already done so, Bassat points out. Although the risk of serious covid complications in this age group is low, vaccination can reduce it even further. In this age group, as in others, the risks of getting vaccinated are much lower than those of covid infection.
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