We are aging as a nation, yet fewer are protecting themselves
A nation that once vaccinated nearly all of its elderly against influenza now protects barely half of them — a quiet unraveling of a public health achievement built over twenty-five years. In Brazil, the relaxation of pandemic-era vigilance has coincided with a demographic shift toward an older, more vulnerable population, and the consequences are arriving in hospital wards and mortality statistics. The story is not merely about a vaccine; it is about how societies forget danger once its most visible face has passed, and what it costs when they do.
- Brazil's flu vaccination rate among adults over 60 has collapsed to 55% in 2023 — the lowest since national campaigns began in 1999, down from a historic high of 95%.
- Hospitalizations from severe influenza among the elderly surged 4.5 times compared to 2022, with 96% of cases requiring inpatient care by May.
- The danger reaches beyond the lungs: doctors are documenting a direct link between influenza infection and cardiovascular emergencies — heart attacks, irregular heartbeats, and stroke — in elderly patients.
- The more aggressive H1N1 strain has returned to circulate among a population that has largely abandoned masks, isolation, and other protective habits normalized during the pandemic.
- Public health experts warn that Brazil is squandering a rare opportunity to embed lasting respiratory hygiene into its culture, as other nations have done, before the next wave deepens the toll.
Brazil's elderly population is contracting influenza at rates not seen in a generation, and fewer of them than ever before are protected by vaccination. Between March and May of 2023, only 55 percent of Brazilians over 60 received the seasonal flu shot — the lowest coverage recorded since the National Immunization Program incorporated influenza vaccination in 1999, and a dramatic fall from the 95 percent the country once routinely achieved.
Dr. Rosana Richtmann of the Emílio Ribas Institute of Infectology described the figures as unprecedented. The timing is particularly troubling: Brazil's population is aging rapidly, meaning more people are entering the age group most vulnerable to serious flu complications precisely as vaccination rates collapse. The results are already visible — severe influenza cases among the elderly surged 4.5 times in 2023 compared to the same period in 2022. Beyond respiratory illness, doctors are observing a growing link between influenza and cardiovascular emergencies, including heart attack and stroke, in the weeks following infection.
About 70 percent of Brazil's elderly already live with at least one chronic condition that amplifies influenza's danger, and the aging immune system offers diminishing natural defense. Vaccination reduces the risk of contracting flu by 60 to 65 percent — yet fewer seniors are choosing it.
Marcelo Gomes of the Oswaldo Cruz Foundation traced much of the decline to a fading sense of risk. Three years of pandemic precautions suppressed respiratory viruses broadly; as those measures lifted and life resumed its familiar rhythms, public vigilance dissolved. Into that opening came H1N1 — a strain more likely to cause severe illness than the variant that dominated in 2022 — circulating among people who have largely stopped masking or isolating when sick. Gomes lamented that Brazil has missed a chance to build lasting cultural habits around targeted mask use, something other countries have successfully achieved.
Deaths from influenza in Brazil rose 135 percent between 2021 and 2022. Respiratory infections now rank as the fourth leading cause of death among elderly Brazilians. Whether the alarms being raised by specialists will be enough to reverse a trend that has left millions unprotected remains the urgent and open question.
Brazil's elderly population has abandoned flu vaccination at a pace not seen since the country began tracking immunization rates a quarter-century ago. Between March and May of this year, only 55 percent of Brazilians over 60 received the seasonal influenza shot—a collapse from the 95 percent coverage the nation once routinely achieved. The drop represents the lowest point in the history of the National Immunization Program, which incorporated flu vaccination in 1999.
Dr. Rosana Richtmann, an infectious disease specialist at the Emílio Ribas Institute of Infectology, called the numbers unprecedented in their severity. "These figures are lower than we have ever seen," she told the Brazilian News Agency on a Friday in late June. The timing of this decline could hardly be worse. According to data from Brazil's continuous household survey, the population under 30 is shrinking while those over 60 are growing significantly—a demographic shift happening not just in Brazil but worldwide. The country is aging rapidly, which means more people are entering the age group most vulnerable to serious flu complications, even as fewer of them are protected by vaccination.
The consequences are already visible in hospital admissions. Cases of severe acute respiratory syndrome caused by influenza among the elderly surged 4.5 times in 2023 compared to the same period in 2022. By May, 96 percent of these cases required hospitalization. The danger extends beyond respiratory distress. Richtmann emphasized that doctors are observing an increasingly direct link between viral infections—influenza among them—and cardiovascular emergencies. Elderly patients who contract the flu face elevated risk of heart attack and irregular heartbeat in the weeks that follow. Those infected with other viruses face heightened stroke risk. The virus, in other words, acts as a trigger for complications that can prove fatal.
About 70 percent of Brazil's elderly population already live with at least one chronic condition—diabetes, hypertension, asthma, chronic bronchitis—that amplifies the danger when influenza strikes. The aging body's immune system naturally weakens over time, a process called immunosenescence, leaving older adults more susceptible to severe infection. Those who do get vaccinated reduce their risk of contracting flu by 60 to 65 percent, or at minimum experience milder illness. Yet fewer are choosing that protection.
Marcelo Gomes, who coordinates the InfoGripe bulletin at the Oswaldo Cruz Foundation, confirmed the sharp drop in elderly vaccination uptake and warned of its ripple effects. He traced part of the decline to a fading sense of danger. For three years, pandemic precautions—lockdowns, masking, distancing—suppressed respiratory viruses across the board. As those measures relaxed and life returned to apparent normalcy, people's perception of risk from influenza evaporated. The virus, meanwhile, seized the opportunity. This year brought the return of H1N1, a strain more likely to cause severe illness than the H2N2 variant that dominated in 2022. It is circulating in a population that has largely abandoned protective behaviors.
Gomes noted that even people showing obvious flu symptoms—sneezing, coughing—have stopped isolating themselves. Those who must venture out while sick should wear masks, particularly on public transit, he said. But Brazil appears to have lost the chance to build a lasting cultural shift around mask use as a targeted tool against respiratory illness, something other countries have successfully embedded in their public health habits. "We are missing a golden opportunity," Gomes told the news agency.
The human toll is mounting. Deaths from influenza in Brazil jumped 135 percent between 2021 and 2022. Respiratory infections now rank as the fourth leading cause of death among elderly Brazilians. The virus continues to circulate, exploiting a moment when vigilance has slipped and immunity has waned. The question facing public health officials is whether the alarm being raised now will be enough to reverse a trend that has left millions of vulnerable people unprotected.
Citas Notables
These figures are lower than we have ever seen. This is the lowest coverage since vaccination campaigns began.— Dr. Rosana Richtmann, infectious disease specialist
We are missing a golden opportunity to build a lasting cultural shift around mask use as a targeted tool against respiratory illness.— Marcelo Gomes, Oswaldo Cruz Foundation
La Conversación del Hearth Otra perspectiva de la historia
Why did vaccination rates drop so dramatically? Was there a specific event or announcement that changed people's minds?
It wasn't one thing. The pandemic suppressed respiratory viruses for years through lockdowns and masking, which made people feel like the danger had passed. As life normalized, that sense of urgency evaporated. People stopped perceiving flu as a real threat.
But the elderly have always been the easiest group to reach for flu shots. What changed there?
That's what makes this so alarming to the doctors. The elderly and healthcare workers were traditionally the reliable ones—they understood the risk. This time, even they stopped coming. The infectious disease specialist called it a paradox: we're aging as a nation, meaning more vulnerable people, yet fewer are protecting themselves.
The cardiovascular complications sound like they're the real story here. Is that new?
Not entirely new, but doctors are seeing the connection more clearly now. A flu infection can trigger a heart attack or stroke weeks later. It's not just a respiratory illness—it's a potential trigger for something much worse. That's why vaccination isn't just about preventing cough and fever.
So what would actually change behavior at this point?
That's the hard question. The researchers point to masks as one tool, but people have decided masks are behind us. They're also hoping the rising hospitalizations and deaths will remind people that the virus is still here, still dangerous, especially for older bodies.
Is H1N1 actually more dangerous than what was circulating before?
It causes more severe illness and hospitalizations than H2N2, which was dominant last year. The timing is terrible—a more aggressive strain arriving when vaccination is at a historic low and people have stopped taking precautions.
What happens if vaccination rates stay this low?
More hospitalizations, more deaths, and a growing burden on a healthcare system already stretched thin. The elderly will bear the worst of it, and the costs—both human and economic—will be substantial.