There are still no studies on the risk of comorbidities in case of re-infection. But experts explain to CNN Portugal what may be at stake for patients who become infected for the second or third time.
Currently, about 15% of the new cases of covid-19 are registered in Portugal reinfections, ie persons (vaccinated or not) who had already been infected. And the percentage continues to rise.
The progressive loss of immunity and the rapid transmutation of the virus are some of the factors contributing to re-infection. Genetic infections usually accompany the emergence of new variants, as immunity from one variant does not automatically provide full protection to another variant. That is also what happens with the flu every year. In the case of SARS-CoV-2, we still do not know how often new variants appear. But we can say that protection against infection has very high values for two to three months and only then begins to decline. A scenario that was further accentuated with the emergence of the Ómicron variant and its underlines.
Faced with a virus that appears to have perfected its ability to invade our immune system, it is important to ask: does re-infection increase the risk of developing covid-19 sequelae?
The answer is still not clear and consensual.
In principle, persons who have not been vaccinated (or whose vaccination is incomplete) and those who have developed a more severe form in the acute phase of the infection are at greater risk of developing long-term covid. But what happens in the event of a re-infection?
“What we do know is that whenever there is a covid-19 infection, even if it is mild or asymptomatic, sequelae can develop, namely at the level of the lungs,” explains Dr. Carlos Palos, specialist in internal medicine and service director. at Hospital Beatriz Ângelo. Therefore, “we can extrapolate and say that with more infections, there can be more cumulative effects,” he adds, but stresses that “there are still no studies” that allow us to reach this conclusion.
“It’s still early days,” confirms Dr. Manuel Carmo Gomes, Professor of Epidemiology at the Faculty of Science at the University of Lisbon. “Studying the effects of long covid takes time.” However, this specialist will “from the start” say that the risk is not greater “because you already have some immune protection”, that is, the body already has a greater ability to defend itself against the infection and prevent the more complicated effects.
What is long covid?
Fever, body aches, fatigue or diarrhea – these are some of the symptoms that covid-19 can cause and that in many patients go beyond the infection. If in some cases they last four, six or more weeks, in others they exceed three months – and this time the data should be a warning sign, doctors guarantee. Having symptoms 90 days after being infected is an indicator that what is known as long covid, a syndrome due to the disease, may be at stake.
The “memory” of the disease.
“The risk of re-infection depends on our immunological past,” explains Carmo Gomes. “Every case is different.”
What happens when a virus attacks our body is that there is a first line of defense made up of antibodies. If these fail, after three or four days a “second-line response” comes into play, consisting of “memory cells” – which hold “remnants of virus” from previous infections. What these cells do is prevent “virus replication” in our body.
For this reason, this specialist believes that people who are re-infected will not only be more responsive to the virus, but as a result, “the risk of long-term covid should not increase”, on the contrary.
The significance of the vaccine
The risk of comorbidities depends on many variables, warns Dr. Miguel Toscano Rico, a specialist in internal medicine. It depends, for example, on whether the person is vaccinated or not (and whether they have the complete vaccination program and booster), when they received the vaccine and what type of vaccine they had, and what strain they were infected with the first time and in subsequent times.
“In vaccinated humans, the risk of developing sequelae of reinfection is not high,” argues Toscano Rico. Having a previous vaccination plan, especially if you have had different vaccines, is a positive factor. If the booster dose is added to this, “the probability of getting an infection is reduced”.
The vaccines were developed for the “wild type” of covid-19, and none of them “proved particularly effective for Ómicron”. In any case, he recalls, vaccines do not prevent infection, nor do they greatly prevent the disease, but they are important in reducing the severity of the disease.
The specificity of Ómicron
Currently, Ómicron is dominant and it is responsible for the high number of reinfections registered in Portugal. Ómicron mainly affects the “upper respiratory tract”, and is e.g. responsible for runny nose and sore throat and less for lung symptoms. And therefore, from the start, with less risk of sequelae, Toscano Rico assesses.
According to several studies, Ómicron is associated with a two-thirds reduction in the risk of hospitalization for covid-19 compared to the Delta variant.
In any case, Carmo Gomes emphasizes, it is necessary to take into account that even people with mild or asymptomatic disease may develop long-term covid, so it can not be said definitively that Ómicron has fewer risks.
To keep the attention on the most vulnerable and not neglected vaccination
The big problem with this peak of reinfections, according to Toscano Rico, is “the equalization of chronic diseases”.
“Right now we do not have the disease with the severity we have seen before, it is visible in the number of hospitalizations and deaths. But it is relatively expected that older people and those with other comorbidities, such as chronic respiratory disease, heart disease or diabetes, are more vulnerable and decompensated, therefore a re-infection of covid-19, as with infection with a normal flu, “can become a serious problem”.
All experts contacted by CNN Portugal insist that vaccination remains our best weapon to combat both the covid-19 infection and its possible consequences. “Booster shots are very important, especially for the most vulnerable people, but not only,” Toscano Rico insists. “Vaccination is the only way we have to fight the serious disease with covid-19.”
“With covid-19, we’re still learning, but we already know this: vaccination is important,” recalls Carlos Palos.