How to differentiate Covid from the common flu, despite increasingly similar symptoms – 07/22/2022 – Equilíbrio e Saúde

Far from what many may think these days, the fact that the symptoms of Covid make it almost impossible to distinguish this disease from others caused by respiratory viruses, such as the flu, does not mean that we should stop worrying or protecting the most vulnerable.

Experts warn that infection rates remain very high among the population and that, although vaccines prevent the development of a serious condition of Covid among those immunized, the most vulnerable people, such as those over 65 or immunosuppressed, remain at risk.

How to distinguish Covid from the flu?

Sore throat, headache, runny nose, stuffy nose and cough are some of the main symptoms that can indicate a Covid-19.

So how do you know if what you are suffering from is the flu or Covid? It’s not possible. The only way to find out is to take a test. Although, according to experts, if you are currently suffering from any of these symptoms, you are more likely to have the coronavirus.

“Covid can have all kinds of symptoms. It can range from having no symptoms at all to having some very similar to those of the flu,” explains Salvador Peiró, a public health specialist and pharmacoepidemiology researcher at Fisabio, a biomedical research foundation in Spain, to BBC News Mundo, the BBC’s Spanish-language news service.

“Right now, we see more dry cough and less problems with anosmia (loss of smell), although there are also cases. Likewise, it can cause anything from mucus in the nose and something more like a very bad cold with fever, a lot of weakness, bad -being in general, tiredness and headache. It varies a lot from person to person”, he adds.

In general, Covid develops a typical picture of respiratory viruses, with some peculiarity in some cases, especially when patients develop problems with loss of taste or smell. But these symptoms are only present between 20 and 25% of Covid cases today, according to Peiró.

“(Covid) is indistinguishable from any other respiratory virus. In fact, if antigen or PCR tests were not performed, we would not know what virus it is. In some cases, there is diarrhea, which sometimes also appears in the flu. But, in general, at this moment, if there is a respiratory condition, the most logical thing is to think that it is Covid”.

According to the specialist, the vast majority of people who are infected with Covid do not even know it or only realize it when they go to the hospital to have a scheduled surgery.

“Actually, between 20 and 25% of people have no symptoms. Others have very mild symptoms, such as a runny nose and a slight sore throat, which can be mistaken for an allergy or something else, but they test positive. Covid can simulate virtually any condition, although at the moment, almost everything that comes from these non-specific symptoms is usually Covid.”

This is the same opinion as Quique Bassat, an epidemiologist and researcher at Icrea (Catalan institute for advanced research) at the Institute of Global Health in Barcelona, ​​a center managed by the “La Caixa” Foundation.

“Mild conditions are not easy to diagnose. The symptoms are very nonspecific. Only if you do a test, to be able to identify. Before it was very easy because it was almost mandatory to do a test. Everyone was anxious to know if they had been infected, for fear of having a serious illness, which motivated him to seek diagnostic confirmation.”

“Now there’s no political or social pressure to do it, or personal pressure, because you don’t care if it’s the flu or Covid, if you don’t risk dying,” says Bassat.

What continues to distinguish Covid from other respiratory viruses is the rate of contagion.

The expert explains that the coronavirus is transmitted much faster than the flu. And that, in a dinner with 15 people, one of them being infected by one of the new variants of Covid, maybe 13 or 14 could end up infected. Already, when dealing with a patient with the flu, the probability is to infect the two that are closest.

“I’m simplifying a lot, but it’s one of the great risks of Covid. It spreads much faster”, warns Bassat.


Although many people currently go through Covid without major problems because they are vaccinated or have had the disease before, others continue to develop severe symptoms and end up in the hospital.

“The truth is that we have everything. We have many asymptomatic people, with minimal symptoms, people who have a picture that looks like the flu and people who continue to have pneumonia.”

“In general, severe cases are associated with age and some previous diseases. But, in principle, the picture is much milder in these new variants than in any other wave”, indicates Peiró.

However, experts point out that the flu can be dangerous for the most vulnerable people, something that also applies to Covid.

“The flu is a very variable measure. We have more ‘calm’ flu years that cause, for example, 4,000 or 5,000 deaths in Spain. But we also have ‘bad’ years, with 15,000 or 20,000 deaths”, he explains.

The expert points out that the flu is not harmless, as much as we sometimes think it is.

“Covid is not either, especially in older or more vulnerable people. For the very young, probably like the flu, the risks are very low. But the elderly should not take it as something banal”, he warns.

“Furthermore, it must be taken into account that the number of infected people is so large that, although serious cases, in proportion to those that exist, are not many, when there are so many infections, there are many serious cases. we see in hospitals and intensive care units (ICUs). Although the disease is less serious, there are many infected and many people who need hospitalization”.

In this way, the most vulnerable must continue to protect themselves, as with the flu.

“The flu kills the vulnerable, it doesn’t kill the healthy people. The flu is essentially a problem for the chronically ill and those over 65. That’s why these populations are vaccinated.

“When all this communication effort was made to try to “influenza” Covid, the idea was to send the same message: that we only have to worry about the most vulnerable, because they are the ones who will continue to be at risk even if they are vaccinated. are currently dying in hospitals,” notes Basset.

Vaccination is key

Although the cases we see now are predominantly benign, upper respiratory tract, nothing serious and with symptoms similar to the flu or cold, this is due not only to new variants of the virus, but also to vaccines, experts explain.

“The virus is now very benign, but because we are vaccinated. The virus has also changed, but we can be more relaxed because, when we are vaccinated, we no longer see such serious cases around us”, says Bassat.

“The heart of the matter is not whether or not Covid looks like the flu. All the variants are different from the others. The crux is that we are vaccinated. That’s what changes the perspective. Any of the new variants can cause a serious condition. among the unvaccinated. There is a very high percentage of the vaccinated population and so it seems to be benign.”

Covid will continue to mutate and we will continue to record waves of this disease, at least for a while.

“We are having more and more reinfections. The new variants easily escape the immunity that covid left with another variant. This means that the waves will not go down”, says Peiró.

In principle, experts hope that the new variants will not be more serious, but it is difficult to know.

“Severe variants may exist, although they are believed to be less severe. Largely because the population will be increasingly infected, they will have immunity from having had Covid or having two, three or four doses of the vaccine.

“However, there is no rule that says that the variants are becoming less severe. There is a rule that says that we are increasingly immunized. The population is much more protected”, says Peiró.

“Vaccines continue to work spectacularly well to prevent serious cases of Covid, between 85% and 90%, according to different studies. This ends up preventing the serious evolution of the condition and that people end up in the hospital”, adds the specialist.