Know the difference between H3N2 flu and Covid-19

Influenza, as it is popularly called, has caused regional outbreaks across the country driven by the introduction of a new strain of subtype A (H3N2), called Darwin. The first identification of the new strain was made in the country by the Instituto Oswaldo Cruz Respiratory and Measles Virus Laboratory (IOC/Fiocruz) in samples from the city of Rio de Janeiro.

To help differentiate influenza from infection with the new coronavirus, the first step is to know the symptoms of each disease.

flu symptoms

The classic symptoms of seasonal flu are sudden fever, cough (usually dry), headache, muscle and joint aches, malaise, sore throat, and runny nose. A cough can be strong and last for two weeks or more, according to the World Health Organization (WHO).

In the case of H3N2, the symptoms are the same, with the potential to cause severe acute respiratory syndrome (SRAG) cases in the elderly and immunocompromised.

“What is changing in this case is that the outbreak is considered out of season and the result of a relaxation of protective measures, such as the use of masks,” explains Renato Astrai, director of the multi-purpose laboratory at the Butantan Institute.

“The problem this year is we’ve been wearing a mask for two years and it’s protective against both influenza and SARS-CoV-2, because it prevents contact with respiratory viruses,” Astray says.

The confluence of the Covid-19 pandemic and a new outbreak of influenza in the country could confuse the identification of cases, as they are two respiratory diseases with similar symptoms.

Cases of H3N2, a subtype of influenza A virus known as Darwin, have spread this year in the northern hemisphere and are currently spreading throughout Brazil causing an increase in the number of hospitalizations.

At the same time, we are still witnessing the Covid-19 pandemic, a disease whose symptoms have changed over time, with new variants emerging.

To help differentiate influenza from infection with the new coronavirus, the first step is to know the symptoms of each disease.

Symptoms of Covid-19

At the start of the pandemic, the World Health Organization reported that those infected had symptoms such as fever, dry cough, fatigue, and loss of taste and smell. After the appearance of variants, the classic symptoms underwent changes.

As the delta variant, which was discovered in India in October 2020, spread across the planet, the most common symptoms of the disease were fever, persistent cough, runny nose, sneezing, headache and sore throat. Similar characteristics to seasonal influenza. Loss of taste and smell is no longer reported.

The omicron infection, which was discovered in South Africa in November, showed another pattern of symptoms, according to Dr. Angelique Coetzee, president of the South African Medical Association. Headache, sore throat and, above all, extreme tiredness you didn’t see in those who contracted the delta.