The viruses that cause the flu (influenza) are quite common. Most likely, you have already been infected by this infectious agent and have experienced some characteristic symptoms of the disease, such as fever, cough and body pain. Despite this, numerous rumors about the infection are disseminated on social networks. Among the most common myths is the recommendation to use antibiotics or that the infection is always mild.
According to the World Health Organization (WHO), every year, between 5% and 10% of the world’s population is infected with the flu virus. This means that something close to 500 million cases of influenza happen annually and, in fact, most of them are mild. However, the infection can be serious, lead the patient to be hospitalized and, in the last case, cause death.
Next, check out 6 biggest myths and truths about the flu, including rumors involving vaccines — which are applied free of charge by the Unified Health System (SUS):
Myth: Antibiotics fight the flu virus
Perhaps the biggest myth about the flu is that it can be fought with antibiotics, which is a lie. As a rule, this class of drugs is adopted for the treatment of bacterial infections and these differ from viral infections, such as that caused by the influenza virus. Even the indiscriminate use of antibiotics contributes to the increase in antimicrobial resistance.
In most cases, doctors will only prescribe medication that relieves the symptoms of the flu, such as decongestants or antipyretics (fever medication). Here, it is important to highlight that, in severe cases of flu, the debilitated patient can develop other infections and bacterial pneumonias. In such cases, the use of antibiotics may be recommended.
Myth: Influenza vaccine transmits the virus live
When a person is immunized against the flu virus, there is no risk of contracting the infection. Although the immunizing formula contains fragments of the infectious agent, it is not “alive” in the vaccine vial. The vaccine can also be applied to pregnant women.
“The influenza vaccine is composed of the fragmented and inactivated virus, therefore, there is no risk of developing influenza from the virus used in the vaccine”, explains the leaflet of the trivalent immunizer against influenza, developed by the Butantan Institute.
Truth: Influenza cases can be serious and lead to death
Although the vast majority of cases of flu are mild, the picture can also be serious. The WHO estimates that every year between 3 to 5 million infected individuals are likely to develop severe symptoms from influenza. On average, 650,000 global deaths are related to the disease, and among these deaths are the elderly, young children and people with comorbidities.
Truth: Flu Vaccination Happens Every Year
Unlike some immunizers, flu vaccination is done every year. This truth can be explained by two main phenomena:
- Virus mutation: the infectious agent is in a constant process of mutation and, for the vaccine to be effective, it must stimulate and sensitize the immune system against those strains that are in greater circulation. These immunizers can protect against three (trivalent) or four (tetravalent) strains;
- Duration of immunity: The other factor that requires vaccination to be annual is the length of time that vaccine-induced immunity persists in the body. “If you get the vaccine in August, you’ll be safe until March, but those antibodies won’t be for the next flu season,” explains Dr Dennis Cunningham, medical director of the Henry Ford Health System in the US, for the live science.
Myth: Flu vaccine will protect against covid
Despite the idea that flu vaccination could offer cross-protection and, therefore, also prevent cases of covid-19, the hypothesis has not been confirmed by scientific studies. Generally speaking, an immunizer only triggers protection against the disease for which it was designed.
“To date, there is no scientific evidence that can infer [indicar] that any vaccine for other diseases [como a da gripe] can prevent covid-19”, explains the Brazilian Immunization Society (SBIm), in a technical note about the 2020 national influenza immunization campaign.
Truth: You can get the flu and covid vaccine together
In Brazil, the Ministry of Health authorizes that the flu vaccine can be applied on the same day as the covid-19 vaccine, except for children under 11 years old. “Ideally, each vaccine should be administered in a different muscle group, however, if necessary, it is possible to administer more than one vaccine in the same muscle group, respecting the distance of 2.5 cm between a vaccine and another, to make it possible to differentiate possible local adverse events”, details a technical note from the folder.
Source: Live Science, Instituto Butantan and SBIm