Have you ever experienced the sudden onset of a cold, fever, cough, and shortness of breath? In most cases, people tend to self-diagnose these symptoms as the flu. Yet unbeknownst to many, these signs could indicate another respiratory illness that remains unfamiliar to the general public: Respiratory Syncytial Virus (RSV).
In an educational forum spearheaded by Pfizer on October 2, 2025, health experts gathered to shed light on RSV, a common, highly contagious, and potentially life-threatening virus that causes lower respiratory tract infections, including bronchiolitis and pneumonia.
This disease can be transmitted through airborne droplets or by direct contact with an infected person or contaminated surfaces.
Part of the tripledemic
Considered by health experts as part of the ‘tripledemic’ (along with influenza and COVID-19), RSV presents with flu-like symptoms. Upper respiratory infections may cause a runny nose, sore throat, headache, fatigue, and fever, while lower respiratory tract infections may lead to a persistent cough, bronchospasm, wheezing, rapid breathing, and shortness of breath.
‘RSV is not something that’s commonly understood or discussed, yet the burden of the disease is very high in the Philippines,’ said Deborah Seifert, MISP (Malaysia, Indonesia, Singapore, Philippines) Cluster Lead. ‘We are taking this awareness initiative to help provide more information to the public because RSV is a real threat.’
Although the virus often goes unnoticed, Dr. Anna Lisa Ong-Lim, Professor of Infectious and Tropical Disease in Pediatrics at the UP-PGH College of Medicine, revealed that the Philippines’ RSV positivity rate ranges from 11 to 20 percent, according to the World Health Organization (WHO) Global RSV Surveillance.
‘In other data, there is seasonality of RSV. In the Philippines, it’s usually during the rainy season,’ she added, highlighting that the disease is most prevalent in the country during the second half of the year.
The discussion also revealed that the virus primarily affects individuals at both ends of the age spectrum, babies and older adults, due to vulnerabilities in their respiratory and immune systems.
‘The problem with young infants is that their airways are small, and when the disease develops, it actually destroys the lining of the airways,’ Dr. Ong-Lim explained.
Infants and young children are particularly susceptible because of their immature organs. The infection can easily clog the airways and may have long-term effects, such as the potential development of asthma. ‘Among adults, we normally have a very good immune system. But for those with what we call ‘comorbidities’ or ‘chronic conditions,’ the bottom line is that their immune system weakens, making them more susceptible to the virus,’ explained Dr. Faith Villanueva, Adult-IDS, Chair of the Philippine Society of Microbiology and Infectious Diseases (PSMID) Vaccination Committee.
Severe RSV infection among older adults with comorbidities can lead to long-term decline in health, including a prolonged decrease in lung function and reduced heart capacity.
Prevention: The First Line of Defense
In the fight against RSV, health experts emphasized the importance of early detection and prevention.
Since the RSV vaccine is not yet readily available for children in the Philippines, Dr. Ong-Lim underscored the importance of diagnosis among adults. ‘Knowing allows you to predict the course and provide specific management to help the illness improve faster. So it’s important to really identify the virus,’ she said.
‘Normally, we test for these viruses using a nasal swab processed through molecular methods like PCR,’ Dr. Ong-Lim explained. She added that specialized swabs are designed for infants and young children when conducting tests on that age group. Rapid testing kits can also be used, though they are generally less accurate.
‘If we are very wary of the flu, then we have to be equally, if not more, aware of RSV,’ Dr. Ong-Lim asserted. ‘What can we do for a viral infection? Typically, it’s to prevent the spread as much as we can. For people who are very sick with any respiratory tract infection, we need to be careful about how we interact with others. Let’s continue to use the masks we got used to during Covid-19, because they truly help prevent the spread of all viral infections.’
Similarly, Dr. Analyn Fallarme, OB-IDS, Vice President of the Philippine Infectious Diseases Society for Obstetrics and Gynecology (PIDSOG), explained that protecting pregnant women involves two main objectives: practicing prevention measures and strengthening the immune system.
‘The difference between pregnant women and others is that their immune system function lowers during pregnancy,’ Dr. Fallarme said. ‘Therefore, they are more prone to infections, and if they contract one, it tends to be more severe-just as we saw with Covid-19.’
To help expectant mothers stay healthy, she shared a set of wellness steps known as ‘N.E.W. S.T.A.R.T.,’ which stands for Nutrients, Exercise, Water, Sunlight, Temperance, Air (fresh), Rest, and Trust in God.
For the elderly, Dr. Villanueva emphasized that prevention and treatment for RSV begin with identifying symptoms and assessing the patient’s overall health.
‘If individuals are truly high-risk, such as those with underlying medical conditions, we recommend testing using a nasopharyngeal [NP] swab to check for the presence of RSV and other viruses,’ she said.
The Status of Vaccination in the Country
At present, a vaccine is available for older adults and pregnant women to provide protection against the virus.
One key measure is maternal immunization, in which the RSV vaccine is administered during pregnancy. The mother’s immune system produces protective antibodies that are then passed to the baby via the placenta. This provides natural defense during the baby’s first vulnerable months of life.
The PIDSOG recommends a single dose of the RSV vaccine for pregnant women from 28 weeks of gestation onwards, but not during active labor. Ideally, vaccination should occur at least two weeks before delivery, and the organization currently does not recommend repeat vaccination in succeeding pregnancies.
‘Pregnant women need to know that they can now protect their babies before they are even born through maternal immunization,’ said Dr. Fallarme.
According to the recommendations of the 2025 Advisory Committee on Immunization Practices (ACIP) and the Centers for Disease Control and Prevention (CDC), adults are also eligible to receive the vaccine. This includes adults aged 75 years and above, those aged 60 to 74 with underlying conditions (such as heart or lung disease, or diabetes), and adults aged 50 to 59 who are at similar risk for severe RSV infection.
‘RSV is not yet included in the mix of vaccines offered by local government units [LGUs]. It’s a new formulation that was just introduced last year,’ clarified Dr. Ong-Lim.
Ultimately, the surveillance system for RSV in the Philippines remains in its early stages. Ongoing efforts aim to gather data that will help health experts and institutions better understand the virus and mitigate its impact on the population.