Epidemic Alerts in the Pacific Region: A Comprehensive Overview

June 3, 2025
|In Health
|By Mridul Upadhyay

1. Dengue Fever Outbreaks

Dengue fever remains a significant concern in several Pacific nations, characterized by periodic outbreaks that strain local healthcare systems.

  • French Polynesia: As of February 2025, French Polynesia reported a cumulative total of 1,158 dengue cases since the onset of the epidemic. The DENV-1 serotype has been predominantly identified, with no fatalities reported to date. Health authorities continue to monitor the situation closely, emphasizing vector control and public awareness campaigns.

  • Samoa: In April 2025, Samoa declared a dengue outbreak following a notable increase in confirmed cases on the island of Upolu. Since January, 15 cases have been reported, with 9 occurring in the past two weeks. The Ministry of Health has intensified efforts to control mosquito breeding sites and educate the public on preventive measures.

  • Tonga: By May 2025, Tonga had reported 647 dengue cases, including three fatalities. The majority of cases were concentrated in the Vava’u and Tongatapu islands. Health officials are focusing on vector control strategies and community engagement to curb the spread of the disease.

2. Influenza Activity

Influenza activity has been observed across various Pacific nations, with some regions experiencing atypical seasonal patterns.

  • New Caledonia: Between November 2024 and January 2025, New Caledonia reported 188 confirmed influenza cases, predominantly of the Influenza A subtype (H1N1 and H3N2). The outbreak has persisted longer than the typical flu season, prompting health authorities to maintain a red alert status and encourage vaccination.

  • French Polynesia: In early 2025, 43 new influenza cases were reported, with a positivity rate of 22%. Thirteen hospitalizations were recorded, including two in intensive care. No deaths have been reported, but the situation remains under close surveillance.

  • Vanuatu: Efate Island in Vanuatu surpassed the alert threshold for influenza-like illness (ILI) in January 2025, with 513 cases reported. While no deaths have been recorded, the National Surveillance Unit continues to monitor the situation and implement control measures.

3. Pertussis (Whooping Cough) Resurgence

Pertussis has seen a resurgence in several Pacific nations, particularly affecting young children.

  • French Polynesia: Between June 2024 and February 2025, 635 pertussis cases were reported. The majority were in children under 10 years old and adults aged 30–39. Health authorities have maintained a red alert status and intensified vaccination efforts.

  • New Zealand: In January 2025, 464 pertussis cases were reported, with a slight increase from the previous month. The Ministry of Health continues to promote vaccination and public awareness to control the spread.

  • New Caledonia: As of January 2025, 204 pertussis cases had been reported, with a recent uptick in January. The blue alert status remains in effect, and health authorities are focusing on early detection and vaccination.

4. Measles Outbreak in Vietnam

While not within the Pacific region, the ongoing measles outbreak in Vietnam has implications for neighboring countries due to potential cross-border transmission.

  • Vietnam: In 2024, Vietnam reported over 45,550 suspected measles cases, with 7,583 confirmed infections and 16 deaths. The World Health Organization has assessed the outbreak risk as very high and recommended large-scale vaccination campaigns in high-risk areas. This situation underscores the importance of regional cooperation in disease surveillance and response.

5. Mpox (Monkeypox) Surveillance

Mpox continues to be a concern in the Pacific region, with sporadic cases reported.

  • Philippines: As of May 2025, the Philippines reported 911 confirmed mpox cases since December 2023, with no fatalities. The Department of Health has been actively monitoring the situation and implementing preventive measures.

  • Australia: Australia has reported 1,680 mpox cases since 2023, with no deaths. The government continues to provide guidance on vaccination and public health measures.

6. Chikungunya Virus

Chikungunya, transmitted by Aedes mosquitoes, has been reported in several Pacific nations.

  • La Réunion (France): In April 2025, La Réunion reported 33,835 confirmed chikungunya cases. The Regional Health Agency has intensified vector control measures and public health campaigns to mitigate the outbreak.

  • Pacific Islands: Other Pacific nations are on alert for potential chikungunya outbreaks, with health authorities monitoring mosquito populations and promoting preventive measures.

7. Surveillance and Response Mechanisms

The Pacific region has established several mechanisms to enhance epidemic surveillance and response:

  • Pacific Syndromic Surveillance System (PSSS): Managed by the World Health Organization (WHO) and the Secretariat of the Pacific Community, PSSS collects and analyzes data on syndromes such as acute fever and rash, diarrhea, and influenza-like illness. This system provides early warning alerts for potential disease outbreaks and facilitates timely interventions.

  • Pacific Public Health Surveillance Network (PPHSN): A voluntary network of countries and organizations dedicated to improving public health surveillance and response to health emergencies in the Pacific. PPHSN harmonizes health data needs, develops surveillance systems, and promotes training programs tailored to regional needs.

Conclusion

The Pacific region faces a complex array of epidemic and emerging disease threats that require coordinated efforts at the national, regional, and international levels. Strengthening surveillance systems, enhancing healthcare infrastructure, and promoting public health education are crucial steps in mitigating the impact of these diseases. Continued collaboration among Pacific nations and with global health organizations will be essential in safeguarding public health and ensuring a resilient response to future health emergencies.