Dengue Vaccination Age Range Expanded in Brazil Amid Surge in Cases

The Pan American Health Organization (PAHO) has declared an "emergency situation" due to a surge in dengue cases across the Americas. PAHO has confirmed over 5.2 million dengue cases this year, a 48% increase from the 3.5 million cases reported last month. More than 1,800 people have died from the mosquito-borne viral illness, up from over 1,000 deaths reported last month.

The countries hit the hardest, Argentina and Brazil, have seen a stabilization or reduction in cases in recent weeks, but the transmission remains strong. In response to the outbreak, Brazil has expanded the age range for dengue vaccination in the Federal District and other states.

The Ministry of Health's directives permit all federative units to broaden vaccination coverage for individuals aged 4 to 59 years. According to Lucilene Florêncio, the Health Secretary of the Federal District (DF), a fresh batch of 12 thousand doses, set to expire in 2025, has been received. This influx enables further consideration for expanding the eligible age group. Once the existing doses nearing expiration are utilized, administration of the new vaccines will commence promptly.

Why this matters: The dengue outbreak in the Americas has reached emergency levels, with millions of cases and thousands of deaths reported. Expanding vaccination efforts is crucial to controlling the spread of the disease and protecting public health.

Dengue symptoms include fever, headaches, vomiting, skin rashes, and muscle and joint pain. In some cases, it can cause a more severe hemorrhagic fever that can lead to death. PAHO warned that the supply of the existing dengue vaccine is "very limited" and widespread vaccination would not have an immediate impact on interrupting the ongoing outbreak.

Dengue vaccine development has been challenging due to the need to induce a balanced immune response against four virus serotypes and the risk of antibody-dependent enhancement (ADE) in individuals with prior dengue exposure. The WHO recommends pre-vaccination screening and only vaccinating those with evidence of previous natural dengue infection, which limits the number of individuals who can be vaccinated in endemic countries.

Despite the availability of some vaccines, there is a lack of specific antiviral treatments for dengue and other arboviruses like yellow fever and Zika. The WHO has launched the Global Arbovirus Initiative to improve surveillance, diagnostics, and the development of new drugs and vaccines to combat these major public health threats.

Key Takeaways

• PAHO declares emergency due to 48% surge in dengue cases in the Americas.
• Over 5.2 million dengue cases and 1,800 deaths reported this year, up from last month.
• Brazil expands dengue vaccination to control outbreak, but vaccine supply is limited.
• Dengue vaccine development is challenging due to the need for balanced immune response.
• WHO launches Global Arbovirus Initiative to improve surveillance, diagnostics, and new treatments.