The virus causing severe cases is mainly influenza A
Each winter season reminds us that the invisible world of viruses does not distinguish between the young and the old, the healthy and the fragile. Across Brazil, a sustained rise in severe respiratory illness — driven chiefly by influenza A and RSV — is pressing hospitals and testing the resilience of communities from the Amazon to the southern coast. Fiocruz's latest data, released in late May 2026, calls not for panic but for the quiet, collective act of vaccination before the window closes.
- Severe acute respiratory syndrome cases are climbing steadily across all of Brazil, with no age group spared from the current wave.
- Influenza A is hitting adults and the elderly hardest, filling hospital beds with the most serious cases, while RSV spreads across all ages and rhinovirus targets children in seven states.
- Three northern and northeastern states — Ceará, Maranhão, and Pará — are flashing early warning signs of a COVID-19 resurgence, even as national numbers remain low.
- Brazil's influenza vaccination campaign expires May 30th in most regions, creating a shrinking but critical window for protection.
- Pregnant women from 28 weeks onward are being urgently directed toward the RSV vaccine, the most direct shield available for newborns in their most vulnerable months.
Brazil is navigating a sustained respiratory illness surge, with Fiocruz's InfoGripe bulletin documenting a steady rise in severe acute respiratory syndrome — SRAG — across every age group during the week of May 17–23. The pressure on hospitals is real and ongoing.
Influenza A stands as the primary driver, responsible for the most serious hospitalizations among young adults, adults, and the elderly. Researcher Tatiana Portella notes that while influenza B has also edged upward, it does not generate the same severity of illness — making influenza A the more urgent concern. RSV, meanwhile, is affecting people of all ages, and in seven states including Amazonas, Rio de Janeiro, and Santa Catarina, rhinovirus has become a significant factor pushing up cases among children and adolescents.
COVID-19 has largely faded as a cause of severe illness nationally, but Ceará, Maranhão, and Pará are showing early upward trends that warrant attention — particularly for the elderly, the immunocompromised, and those with underlying conditions who are urged to keep their boosters current.
The Ministry of Health's influenza vaccination campaign runs through May 30th across most of the country, with the North to be reached later in the year. A parallel effort targets pregnant women at 28 weeks or beyond, encouraging them to receive the RSV vaccine to protect their newborns during the most fragile months of life. The tools to blunt this wave exist — the question is whether enough people will use them in time.
Brazil is in the grip of a respiratory illness surge. The latest weekly report from Fiocruz, released Thursday, May 28th, documents a steady climb in cases of severe acute respiratory syndrome—known as SRAG—spreading across the country and touching every age group. The data covers the week of May 17 through 23, and the picture it paints is one of sustained pressure on hospitals dealing with respiratory disease.
Influenza A is the principal culprit. In adults and elderly populations, this virus has become the dominant cause of the most serious respiratory hospitalizations. Tatiana Portella, a researcher tracking the outbreak through Fiocruz's InfoGripe bulletin, explains that while influenza B has also ticked upward slightly, it does not produce the same severity of illness. "The virus causing the increase in severe cases among young adults, adults, and elderly people is mainly influenza A," Portella said. "We have seen a slight rise in hospitalizations from influenza B, but that virus doesn't generate as many grave cases as influenza A does. So even though influenza B cases are rising, the increase isn't nearly as pronounced."
Respiratory syncytial virus, or RSV, is another major driver, affecting people across all ages. In seven states—Alagoas, Paraíba, Sergipe, Minas Gerais, Rio de Janeiro, Amazonas, and Santa Catarina—rhinovirus has emerged as a significant factor pushing up SRAG cases among children and adolescents. The virus is moving through the population with little resistance.
COVID-19, by contrast, has largely receded as a cause of severe illness nationwide. But the picture is not uniform. Portella notes that while most of the country has seen COVID-19 hospitalizations stay low, three states are showing early warning signs: Ceará, Maranhão, and Pará are beginning to record upward trends in severe COVID cases. For this reason, she emphasizes, people in high-risk categories—the elderly, the immunocompromised, those with underlying health conditions—need to stay current with their booster shots.
The Ministry of Health is running a vaccination campaign against influenza that extends through Saturday, May 30th, across the Northeast, Center-West, South, and Southeast regions. The campaign will reach the North in the second half of the year. There is also a specific push for pregnant women at 28 weeks or beyond to receive the RSV vaccine, which protects newborns in their most vulnerable first months of life. The window to act is narrow, and the stakes are clear: vaccination remains the most reliable defense against the viruses now circulating.
Notable Quotes
The virus causing the increase in severe cases among young adults, adults, and elderly people is mainly influenza A. Even though influenza B cases are rising, the increase isn't nearly as pronounced.— Tatiana Portella, Fiocruz InfoGripe researcher
COVID-19 cases have remained low in most of the country, but we are observing a growth trend in some states like Ceará, Maranhão, and Pará, which is why it's important for high-risk populations to stay current with booster doses.— Tatiana Portella, Fiocruz InfoGripe researcher
The Hearth Conversation Another angle on the story
Why is influenza A causing such severe illness when influenza B is circulating at the same time?
The viruses have different properties. Influenza A has a particular capacity to trigger the kind of systemic response that lands people in the hospital with acute respiratory distress. Influenza B tends to stay milder, even when it spreads. We're seeing both, but only one is filling the beds.
The report mentions RSV affecting all ages. That's unusual, isn't it?
RSV typically hits hardest in infants and the elderly. But this season it's moving through the whole population. That's why the vaccine push for pregnant women matters so much—if you can give a newborn passive immunity from the mother, you buy them protection in those first critical months when they can't be vaccinated themselves.
Three states are showing COVID growth signals. Does that suggest a new variant is emerging?
The report doesn't specify. It's just flagging that after months of decline, those three states are seeing the curve tick upward. It's early. But it's a reminder that the virus hasn't gone away—it's just waiting for conditions to shift.
Why does the vaccination campaign not reach the North until the second half of the year?
Logistics. The North is vast and dispersed. Getting vaccines to remote areas takes planning and resources. But it also means people there are unprotected during the peak season happening right now.
If someone is already sick with SRAG, what can they do?
The report doesn't address treatment—it's focused on prevention. But the implication is clear: once you're hospitalized with severe respiratory syndrome, you're already in crisis. The vaccine is meant to stop you from getting there in the first place.