At least four cities in Rio de Janeiro have registered an increase in cases of flu-like illness in the last three weeks, according to a survey carried out by CNN. In Rio de Janeiro, 21 thousand people were diagnosed with influenza A (H3N2) during this period.
According to researchers at the Oswaldo Cruz Institute (IOC/Fiocruz), who monitor the virus in Brazil, the circulating strains have been similar to those circulating in other countries and are included in the vaccine that will be applied in 2022 in the southern hemisphere .
H3N2 is a subtype of the influenza A virus. “It is not a new virus, H3N2 has been infecting humans since 1968 and has been circulating predominantly since 2015 in Brazil and worldwide,” said virologist Fernando Motta, from Fiocruz, in the Rio de Janeiro.
According to the researcher, the increase in the number of flu cases may be associated with the relaxation of preventive measures against Covid-19, such as wearing a mask and social distancing.
The prevention measures against the common flu are the same used to prevent the infection by Covid-19:
- use of masks
- hand hygiene with soap and water
- use of alcohol gel
- keep the rooms ventilated
- do not touch eyes and mouth constantly
- avoid crowds and closed places
- adhere to the flu vaccination
Different Types of Flu Viruses
There are three types of Influenza viruses: A, B and C – the first two are responsible for seasonal epidemics in various regions of the world, with circulation predominantly in winter and the last one, causing milder infections. Type A is classified into subtypes such as A(H1N1) and A(H3N2).
“Every year, epidemics are caused by variants of three main viruses that circulate in the human population, two of which are type A: influenza A(H1N1)pdm09 and A(H3N2), and influenza B, which has no subtypes, but two lineages: Victoria and Yagamata”, explains researcher Paola Resende, from Fiocruz.
According to the researcher, although there are genetic differences, all types of influenza viruses can cause the same symptoms, such as high fever, cough, sore throat, headaches, in the body and joints, chills and fatigue.
Virologist Fernando Motta, from Fiocruz, explains that the circulation of flu viruses varies from year to year. According to him, vaccination is the main way to prevent the development of more severe cases of the disease.
“Vaccines are updated for each epidemic, and even if only one component is changed, it is important to renew the vaccination. Another desired aspect is the effect caused by the new vaccine, which reinforces the defenses activated in the previous year”, he said.
In September, the Ministry of Health suspended the application interval between the flu and Covid-19 vaccines, in order to facilitate the population’s adherence to the two immunization campaigns.
*With information from Camille Couto, from CNN, in Rio de Janeiro
Reference: CNN Brasil
