There are no studies yet on the risk of sequelae in the event of reinfection. But experts tell CNN Portugal what could be at stake for patients who are infected for the second or third time.
Currently, around 15% of new covid-19 cases registered in Portugal are reinfections, that is, people (vaccinated or not) who had already been infected. And the percentage keeps increasing.
Gradual loss of immunity and rapid transmutation of the virus are some of the factors that contribute to the reinfection. Reinfections usually accompany the emergence of new variants, because immunity against one variant does not automatically provide complete protection against another variant. This 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 the protection against infection has very high values for two to three months and only then begins to decline. A scenario that has been further accentuated with the emergence of the Ómicron variant and its sub-lines.
Faced with a virus that seems to have perfected its ability to invade our immune system, it is important to ask: does reinfection increase the risk of developing covid-19 sequelae?
The answer is still not clear and consensual.
In principle, people 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 covid. But what happens in case of reinfection?
“What we know is that in theory, each time there is a covid-19 infection, even if it is mild or asymptomatic, sequelae can develop, especially in the lungs. “, explains doctor Carlos Palos, in-house specialist. medicine and service director at the Beatriz Ângelo Hospital. Therefore, “we can extrapolate and say that with more infections there may be more cumulative effects”, he adds, stressing however that “there are still no studies” which lead to this conclusion.
“It’s still early,” confirms Doctor Manuel Carmo Gomes, professor of epidemiology at the Faculty of Sciences of the University of Lisbon. “Studying the effects of a long covid takes time.” However, “from the start”, this specialist would say that the risk is not greater “because you already have some immune protection”, that is, the body already has more capacity to defend itself against infection and to prevent more complicated effects.
What is covid long?
Fever, body aches, fatigue or diarrhea – these are some of the symptoms that covid-19 can cause and which in many patients extend beyond infection. If in some cases they last four, six weeks or more, in others they exceed three months – and this time the data should be a warning signal, guarantee the doctors. Having symptoms 90 days after being infected is an indicator that is called long lusta syndrome resulting from the disease.
The “memory” of the disease
“The risk of reinfection 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 which is antibodies. If these fail, after three or four days a ‘second-line response’ kicks in, consisting of ‘memory cells’ – which retain ‘virus remnants’ from previous infections. What these cells do is prevent “virus replication” in our body.
For this reason, believes this specialist, not only will reinfected people be more reactive to the virus, but, as a result, “the risk of long covid should not increase”, on the contrary.
The importance of the vaccine
The risk of sequelae depends on many variables, warns doctor Miguel Toscano Rico, specialist in internal medicine. It depends, for example, on whether the person is vaccinated or not (and if they have the full vaccination schedule and booster), when they received the vaccine and what type of vaccine they had, and the strain they were infected the first time and in the following times.
“In vaccinated people, the risk of developing sequelae during reinfection is not high,” says Toscano Rico. Having a previous vaccination schedule, especially if you have received different vaccines, is a positive factor. If the booster dose is added to this, “the likelihood of getting an infection is reduced”.
The vaccines were developed for the “wild type” of covid-19 and none of them “proven to be particularly effective for Ómicron”. In any case, he reminds us, vaccines do not prevent infection, nor do they largely prevent disease, but they are important in reducing the severity of the disease.
The specificity of Ómicron
Right now it’s Omicron which is dominant and responsible for the high number of reinfections recorded in Portugal. Ómicron mainly affects “the upper respiratory tract”, being responsible, for example, for runny nose and sore throat and less for pulmonary symptoms. And so, from the start, with less risk of sequelae, considers Toscano Rico.
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, emphasizes Carmo Gomes, it must be taken into account that even people with mild or asymptomatic illness can develop a long covid, so it cannot be said definitively that Ómicron presents less risk.
Pay attention to the most vulnerable and do not neglect vaccination
The big problem with this spike in reinfections is, according to Toscano Rico, “the decompensation of chronic diseases.”
“At the moment we don’t have the disease with the severity that we have seen before, it shows in the number of hospitalizations and deaths. But it is relatively expected that the elderly and those with other comorbidities , such as chronic respiratory disease, heart disease or diabetes, are more vulnerable and decompensated. Therefore, a reinfection of covid-19, like infection from a normal flu, “can become a serious problem”.
All the experts contacted by CNN Portugal insist that vaccination remains our best weapon to combat both covid-19 infection and its possible consequences. “The recalls are very important, especially for the most vulnerable people but not only,” insists Toscano Rico. “Vaccination is the only way we have to fight the serious disease of covid-19.”
“With covid-19, we are still learning, but this we already know: vaccination is important”, recalls Carlos Palos.