SP: Positive tests for dengue and influenza increase – 04/04/2024 – Health

The city of São Paulo has shown an increase in positivity rates for dengue and influenza (the virus that causes the flu) in the last week, according to a survey by the Dasa network.

On the other hand, tests carried out for Covid with positive results also fell in the last week.

The drop in Covid test positivity follows the same line in the country as a whole: the rate decreased by 40.6% in Brazil and 39.6% in São Paulo between the weeks of March 12th to 18th and 19th 25th of the same month. Positivity refers to the number of tests with positive results.

On the other hand, there was an increase of 3 percentage points in the positivity rate of influenza tests in the capital between March 17th and 30th: from 24% to 27%.

The increase was 6.8 percentage points in the dengue rate. There were 33.3% positive tests between March 17th and 23rd and 40.1% between March 24th and 30th.

The positivity rate refers to the number of tests carried out in the laboratory with a positive result for one of the viruses.

The growth of dengue fever in the capital has been constant since March 10, according to the survey. Positive tests represented 23.8% of the total between the 10th and 16th. Dasa did not say how many tests were carried out in total, but stated that there are more than 900 diagnostic units in Brazil.

On March 18, São Paulo City Hall declared a state of emergency due to a dengue epidemic. The management’s forecast is that the city will reach a plateau (that is, when there is a stabilization of new records before the drop) of cases in April.

RSV (respiratory syncytial virus), which causes complications mainly in children, recorded a slight drop in positivity in the capital: from 7.9% to 7.7% between March 17th and 30th. This may indicate that there is stability in virus rates.

On Monday (1st), Anvisa (National Health Surveillance Agency) approved the first vaccine for pregnant women that protects babies up to one year old against RSV, the main cause of acute respiratory infections in babies up to six months of age, such as bronchiolitis.

Experts have already pointed out that there is an unseasonal outbreak of respiratory syndromes. According to virologist José Eduardo Levi, the anomalous peak of influenza at the beginning of the year could result in a lower intensity from autumn to winter.

The increase in dengue fever is an expected behavior, since the peak of cases of the disease occurs in April. “In São Paulo, the epidemic is still expanding,” he says.

On the 25th, flu vaccination began by the government of the state of São Paulo. The vaccine administered by the Ministry of Health is trivalent — made up of two strains of influenza A and one of B — and can be taken at the same time as other vaccines.

According to the director of CVE (Epidemiological Surveillance Center of the State Department of Health), Tatiana Lang D’Agostini, the arrival of autumn brings a greater prevalence of respiratory diseases such as rhinitis, sinusitis, flu and colds. The change of season can favor an increase in cases and vaccination can prevent this scenario.

Despite the drop in positivity in coronavirus tests, the level still makes it difficult to differentiate flu-like syndromes, says the virologist.

In the last year, Covid symptoms have become milder, due to the omicron subvariants, which infect more of the throat and nose (upper airways). Even so, flu and Covid symptoms can be confused. Covid can also present gastrointestinal symptoms in adults and, in children, cause pediatric multisystem syndrome (SIM-P), which can lead to complications.

Furthermore, the symptoms of long Covid, which occur up to three months after infection, can leave neurological, cardiac and even vascular sequelae. Up-to-date vaccination helps prevent sequelae and serious illness from the disease.