The Department of Health (DOH) reported that nationwide influenza-like illness (ILI) cases from January 1 to September 27, 2025 totaled 121,716, about 8 percent lower than the same period in 2024. Health officials emphasized that the continued presence of respiratory symptoms reflects expected seasonal patterns, not an outbreak.
National authorities clarified that there is no influenza outbreak or new viral strain circulating. Instead, typical rainy-season and year-end transmission of cough, colds, and fever-related illnesses continues as the country goes through December.
In the United States, the Centers for Disease Control and Prevention (CDC) designated December 1–5, 2025 as National Influenza Vaccination Week (NIVW), underscoring that vaccination remains important while flu viruses continue to circulate.
Public-health specialists note that the reminder is timely for the Philippines, where holiday travel, indoor crowding, and family gatherings can raise the risk of respiratory transmission. Globally, influenza activity also remained elevated in late 2025, according to the World Health Organization (WHO), with positivity rates exceeding 20 percent in several Northern Hemisphere regions.
Seasonality of influenza-like illness in the Philippines
The DOH’s October update highlights the seasonal nature of respiratory illness in the country. From January through late September 2025, ILI cases totaled 121,716, compared with 135,538 cases during the same period in 2024.
Despite speculation circulating on social media in October, Health Secretary Teodoro Herbosa repeatedly clarified that the rise reflected seasonal flu activity, not an outbreak. “Wala pong outbreak … it’s the seasonal flu, and we still have to be careful,” he said, explaining that ILI encompasses symptoms caused by multiple respiratory viruses.
Some localities, however, have reported notable increases. According to Philippine Star reporting, the provincial government of Quezon reinstated mask recommendations after ILI cases there rose by 130 percent compared with the previous year.
The DOH stressed that such localized increases do not signal a nationwide outbreak, but still warrant preventive measures such as hand hygiene, cough etiquette, and voluntary mask use for symptomatic individuals.
ILI versus laboratory-confirmed influenza
Health authorities emphasize the importance of distinguishing between ILI and laboratory-confirmed influenza. WHO defines ILI as a clinical syndrome—typically fever with cough or sore throat—that resembles influenza but may be caused by different respiratory pathogens.
As such, an increase in ILI does not automatically mean confirmed influenza cases are rising. Instead, it signals heightened respiratory illness activity that public-health systems monitor for early response.
DOH clarifies that ILI can be caused by influenza A and B, rhinoviruses, and other respiratory viruses, unlike COVID-19, which is caused by a single virus. This distinction helps explain why ILI trends may fluctuate even in the absence of a declared influenza outbreak.
National Influenza Vaccination Week: a global reminder
Although NIVW is a U.S.-based observance, its message applies broadly. According to the CDC’s 2025 NIVW guidance, December 1–5 is a reminder that “there’s still time to get vaccinated against flu this season,” and that vaccination remains the most effective way to reduce illness, hospitalization, and death.
The CDC also stresses that vaccination is particularly important for people at higher risk of complications, including pregnant women, young children, older adults, and individuals with chronic conditions.
In the Philippines, influenza vaccination messaging tends to receive less public attention, despite similar seasonal risks. Public-health experts argue that aligning vaccination reminders with local factors—such as holiday crowding and travel—may help sustain uptake, especially among high-risk groups.
READ: How Innovation Is Transforming Filipino Wellness
Recent Philippine vaccination figures
A reference point for influenza vaccination coverage in 2025 comes from a UNICEF Philippines press release dated April 24, 2025. According to UNICEF, influenza vaccine coverage reached 65.57 percent among eligible populations, including senior citizens, healthcare workers, and individuals with comorbidities.
The figure formed part of broader immunization-equity reporting involving DOH and WHO partners, indicating that a substantial proportion of priority groups had received seasonal influenza vaccination.
However, DOH has not released a comprehensive nationwide breakdown for influenza vaccine coverage for the latter part of 2025. Coverage also varies locally depending on supply, distribution, and demand, meaning the reported rate offers a useful snapshot but not a complete national picture.
WHO surveillance and global context
Globally, influenza remained active in late 2025. WHO’s surveillance update for late November showed influenza positivity rates above 20 percent in several Northern Hemisphere regions, with influenza A viruses predominating.
WHO data also indicate that while COVID-19 activity remained relatively low overall, influenza continued to circulate widely. These patterns support continued emphasis on vaccination—not only for local protection, but in a global environment where influenza transmission persists.
Who is most vulnerable to severe influenza
WHO guidance consistently identifies certain groups as being at higher risk for severe influenza outcomes. These include pregnant women, children under five, older adults, people with chronic medical conditions, and healthcare workers.
In the Philippines, adults aged 60 years and older are a particular focus due to documented influenza-associated excess mortality in this age group. Previous studies have shown that a large proportion of influenza-attributable deaths occur among older adults, reinforcing the importance of prioritizing vaccination and preventive care.
Access for seniors and remaining challenges
Influenza vaccination policy in the Philippines includes provisions for vulnerable groups. In previous DOH guidance, influenza vaccines were made available free to indigent senior citizens through Centers for Health Development clinics and partner facilities, a policy reported by Philippine media during the 2025 season.
While these efforts improve access, challenges remain, particularly in rural areas and among individuals with limited mobility or resources. Vaccine hesitancy—documented in earlier Philippine studies on adult immunization—also continues to affect uptake and requires sustained public-health communication.
Weather, crowding, and transmission risks
Seasonal weather patterns influence respiratory transmission. In October 2025, the PAGASA announced the transition from the Southwest Monsoon (Habagat) to the Northeast Monsoon (Amihan).
Although heavy rains typically lessen, behavioral factors such as indoor gatherings, holiday travel, and shopping increase in December. Public-health experts note that close proximity in poorly ventilated spaces facilitates the spread of influenza and other respiratory viruses.
Prevention beyond vaccination
While vaccination remains the most effective protection against severe influenza, DOH emphasizes layered prevention strategies. These include regular handwashing, covering coughs, improving indoor ventilation, and staying home when ill.
Mask use in crowded or high-risk environments is also advised for symptomatic individuals, even if not nationally mandated. Health authorities reiterate that these everyday measures complement immunization efforts.
Why December messaging matters
Although influenza peaks in the Philippines may occur earlier in the year, ILI activity extends into December. Combined with increased travel and gatherings, this makes year-end messaging particularly relevant.
Verified national data confirm that ILI levels in 2025 remain within expected seasonal patterns, without evidence of a national outbreak. Nevertheless, respiratory viruses continue to circulate, and global influenza activity remains elevated.
Health officials stress that combining vaccination with preventive behaviors offers the strongest evidence-based approach to protecting vulnerable populations during the holiday season and beyond.
Photo from Baclaran Phenomenon
