A Surge in Hepatitis A Cases in São Paulo! Exploring Urban Life and Health Risks

1. Introduction: Cold Sweat in the "Yellow July"

In Brazil, July is annually referred to as "Julho Amarelo" (Yellow July) and is designated as Hepatitis Awareness Month. However, in 2025, the news heralding its commencement was more of a warning than a celebration. The number of hepatitis A cases in São Paulo State had surged to 974 in just half a year—an increase of approximately 1.9 times from the 498 cases during the same period the previous year.InfoMoney

Posts such as "I'm scared of tap water now" and "What should I do about my child's lunch?" quickly spread across social media, making the public's anxiety visible in real-time. The author's notification box was also filled with direct messages from both domestic and international sources asking, "What's happening on the ground?" In this article, we will comprehensively analyze the background of the surge in hepatitis A cases and the challenges ahead by examining public data, local media, expert interviews, and the "raw" voices from social media.

2. The Impact of "974 Cases, 90% Increase" by the Numbers

According to statistics released by the State Health Department (SES-SP) on July 12, the number of reported hepatitis A cases from January 1 to July 8, 2025, was 974. Even for a state with a population of 100 million, this figure far exceeds the usual threshold. The breakdown of infection routes is as follows:

• Contaminated water/food:66%

• Sexual transmission (mainly among MSM):24%

• Unknown/Other:10%
  .InfoMoney

Meanwhile, during the same period, there were 560 cases of hepatitis B (2,483 cases for the entire previous year) and 641 cases of hepatitis C (3,159 cases for the entire previous year), highlighting the exceptional increase in hepatitis A cases.

3. Cause ① Infrastructure Aging and Heavy Rain

In the northern part of São Paulo City, intermittent heavy rains since the end of 2024 have caused frequent water pipe breakages, and the arrangement of temporary water supply trucks has not kept pace. According to the municipal water company Sabesp, "The environment during emergency repairs made it easy for soil microorganisms to mix in." As a result, the use of well water and rainwater by traditional markets and stalls increased, expanding the fecal-oral infection route.

4. Cause ② Post-Pandemic "Vaccine Gap"

During the COVID-19 pandemic, basic vaccination rates declined across the board. The state average coverage rate for the hepatitis A vaccine (two doses) dropped from 91.4% in 2019 to 80.7% in 2023. The health department began a large-scale catch-up vaccination campaign in April 2025, and by July, they had managed to recover the rate to 87%, but they were unable to preempt the outbreak.

5. Cause ③ Internationalization of Sexual Networks

São Paulo hosts the largest LGBTQ+ community in South America, and its annual Pride Parade in June attracts tourists from around the world. The 24% figure for sexual transmission resembles patterns of MSM group outbreaks reported in Europe from 2017-19, suggesting that the recovery of international human flow may have created new transmission routes.

6. State Government's "Visualization" Strategy—Panel Launched on July 9

In response to the surge, State Health Director Tabata Amaral launched the **"Water and Foodborne Disease Monitoring Panel"** on July 9. The dashboard graphically displays the number of cases by municipality, incidence rates by age group, and vaccination rates, and provides data to external developers via API.saude.sp.gov.br

7. The Spread of "Voices" and "Misinformation" on Social Media

Within 24 hours of the monitoring panel's release, posts with the hashtag "#HepatiteA" exceeded 110,000. Some excerpts include—

• "When will Sabesp officially acknowledge the contamination route?"

• "Sharing a map of free vaccine venues!" (with Google Maps link)

• "The sewage is fine. This is government propaganda." (misinformation)
  The state government quickly assembled a fact-checking team and began posting "rumor verification cards" on its official Twitter every night. It was also revealed that half of the accounts spreading false information had foreign IPs.Instagramotempo.com.br

8. Expert Opinion—Speaking with a Hepatologist

Dr. Eloísa Hippolito, a professor of hepatology at Rio State University, warns, "Hepatitis A does not become chronic, but the risk of fulminant hepatitis is higher in adults. Young people with alcohol consumption habits are particularly prone to severe cases," and recommends early diagnosis and 'antibody titer confirmation within 90 days.'

9. Comparison: Global Trends in Hepatitis A

According to the WHO European Office, there were approximately 15,000 reported cases of hepatitis A in Europe in 2024, with 69% foodborne. São Paulo State, when viewed in terms of population ratio, has an incidence rate about twice the European average, making it a high-risk area internationally.

10. Citizen Interviews

• Camila Rossi (25, University Student)

  "I started avoiding salads at the university cafeteria. All my friends went for additional vaccinations."

• André Sanchez (41, Stall Owner)

  "Due to increased health department inspections, I was instructed to play handwashing videos at the storefront."

11. Corporate Responses—Beverage and Food Industry

Major juice manufacturer Do Bem increased the frequency of raw material inspections from once to three times a week. UberEats Brazil mandated affiliated restaurants to submit hygiene checklists and implemented a new feature to display "under hygiene investigation" for violating stores on the app.

12. Education Sector—"Yellow School Lunch Day"

Starting July 15, the state education department piloted "Yellow School Lunch Day" in all public schools. Menus featured liver-friendly foods (legumes and green-yellow vegetables), and classes included a "hepatitis quiz." Participation reached 76% on the first day.

13. Challenges—The 83% Sewage Coverage Barrier

São Paulo State's sewage treatment coverage rate is 83%, the highest in the country, but unconnected suburban areas have emerged as infection hotspots. Experts estimate that achieving 100% connection would require an investment of approximately 8 billion reais over five years.

14. Future Scenario Predictions

15. Conclusion—How to Face the "Invisible Enemy"

Hepatitis A is a disease that can be almost 100% prevented with vaccines and hygiene management. Yet, gaps in urban infrastructure and information disparities create opportunities for infection. São Paulo's experience offers three lessons to the world: "post-pandemic vaccine gap," "misinformation countermeasures in the age of social media," and "updating aging infrastructure." The actions we should take are simple: ensure clean water, get vaccinated, and verify information. This practice can transform the yellow ribbon warning into a symbol of hope.