As the vaccination campaign progresses around the world, the issues that concern patients who receive them coincide.

A sanitary vaccinating a woman in Seville.

At the beginning of April, more than 360 million people worldwide had received at least one dose of a Covid-19 vaccine, which is close to 5% of the world population according to Our World in Data. Although doubts and reluctance about the new drugs are a minority -in Castilla-La Mancha there were 15% of teachers who refused to receive the AstraZeneca vaccine, a percentage described as “very low” by the counseling-, they have been replaced by others about the efficacy of the antigen once it has been inoculated.

The editor of the Health section of The New York Times, Tara Parker-Pope has compiled the most frequently asked questions from Americans, in a country that is vaccinating a rate of three million daily doses. Most of the doubts at this point relate to the fear of possible contraindications to other medications, the uncertainty about whether the vaccine will have the desired effect, and the unknown of how long immunity will last against the appearance of new variants.

Can I take ibuprofen before or after?

Ibuprofen has already starred in a few weeks of confusion with the arrival of the pandemic in the West, when there were doubts as to whether it was effective or counterproductive for the symptoms of Covid-19. Now, while the health authorities in Spain recommend take a dose of this inflammatory before receiving the vaccine, particularly if it is the AstraZenecaSome of their counterparts in the US request the opposite, that drugs that may interfere with immune action be avoided.

The answer, based on a review of studies on 5,000 children vaccinated against different diseases, is that yes either taking pain relievers before or after can interfere with the immune system, they do not affect the success of the vaccination, so they can be taken. 26% of the volunteers of Moderna’s drug took paracetamol, and its efficacy was maintained at 94%.

If I don’t have a reaction to the vaccine, does that mean it is not working?

Most of the side effects that have been reported after the vaccines include bothersome symptoms that have forced some patients to save every day or two, such as fever or muscle aches. There has been so much talk about these adverse events that Some people, noticing nothing but numbness in the puncture area, have wondered if the drug is really working, since there seems to be no immune reaction.

However, the rate of volunteers reporting no side effects during the Pfizer trials was one in four, and in Moderna’s case, one in five, without compromising the high efficacy rate. It is therefore minority, but not exceptional, passing the vaccination without discomfort. The reason why the experience differs so much from one individual to another is largely unknown: it is known, for example, that the elderly tend to have fewer reactions to have a weaker immune system, but at the time Actually, the acquisition of immunity will have different effects on each one.

Do women suffer worse side effects than men?

Like age, biological sex also makes a difference. The immune response is usually stronger in women, among other reasons, due to estrogens, hormones that tend to stimulate it while testosterone, more present in men, attenuates them. It is known that young women vaccinated against influenza, hepatitis and MMR develop antibodies twice as fast as men of the same age, and on the other hand, it is they who have suffered 80% of the cases. Anaphylactic reactions to vaccines in the USA.

Thus, although men have a higher risk of mortality linked to Covid-19, women women are therefore more likely to suffer side effects, according to the study that was done on the first 13.7 million vaccinated Americans. The work, Parker-Pope cites, found that cases of anaphylaxis or life-threatening allergic reaction were very rare during this vaccination, but that almost all cases corresponded to women.

Are the side effects worse after the second puncture?

Yes, based on the results in the United States: In the case of the Pfizer vaccine, cases of fatigue increased by 29% after the first dose to 50% after the second; muscle pain appeared in 17% of cases with the first puncture and in 42% with the second; and reports of chills went from an incidence of 7% to 26% from the first to the second injection. Given that the US does not restrict these drugs by age, and due to the idiosyncrasies of its health and labor systems, there are doctors who are recommending that workers who are going to receive the second dose of Pfizer or Moderna “ask for a few days off” before.

If I have already passed Covid-19, will the symptoms be worse?

According to Paker-Pope, there are indications that, indeed, the immune response to the first dose of the vaccine is stronger when the person has passed the Covid-19. In fact, a powerful reaction to this first inoculation would indicate to healthcare professionals that the patient has been able to contract the disease asymptomatically in the past and you do not know it, if you have not had an antigen or serological test.

Will I have to get vaccinated again for the coronavirus variants?

It’s the million dollar question: humanity and the SARS-CoV-2 they fight a race, that of immunization against that of variants that can find weaknesses in the defenses and become dominant, as has happened brilliantly with the ‘British variant’, as well as those that were identified in Brazil or South Africa.

It is plausible to think that, given the appearance of new strains in less protected countries, at some point current vaccines will fall below a minimum efficacy threshold. Therefore, the hypothesis of a third dose of souvenir in two or three years.