Response:

Flu and the common cold are two prevalent respiratory infections, and they are distinct diseases. Flu is typically caused by influenza A and B viruses, while the common cold can be caused by over 200 different viruses, most commonly Rhinovirus. Flu symptoms are usually more severe and dangerous than those of a cold. The illness can lead to complications such as pneumonia, respiratory failure, meningitis, and worsen existing man tinh diseases.

In temperate countries like the United States, United Kingdom, and France, the peak flu season usually occurs from december to february, so flu vaccines are best administered from september to october. In countries with a tropical monsoon climate like Vietnam, flu can appear year-round, with virus activity varying by region and time.

For tropical countries experiencing multiple flu surges throughout the year, the World Health Organization (WHO) recommends vaccination before the main local increase in flu activity. Therefore, you do not need to wait for a fixed month to get a flu vaccine. The appropriate time depends on your most recent vaccination. If your annual vaccination is due or if you have not been vaccinated, you can visit a medical facility for screening and consultation; you should not delay just to wait for april or october.

Flu vaccines can be administered any month of the year, regardless of april or october. *Photo: Moc Thao*

After vaccination, the body typically needs about two weeks to develop protective antibodies. Therefore, if your area reports an increasing trend in flu cases, or if you are about to travel, go on vacation, or enter crowded environments, you should proactively get vaccinated rather than waiting for an outbreak to become evident. However, you should not shorten the interval between two doses. Individuals who received their last flu vaccine less than one year ago need to provide the vaccination date and type of vaccine used so doctors can determine if another dose is necessary. The interval between two flu vaccine doses should be at least 6 months.

Annual flu vaccination is recommended because protection wanes over time, while the flu virus continuously mutates. Vaccine components are also updated based on predictions of the virus strains likely to circulate in the upcoming season. Therefore, the key is not to choose the same month every year, but to maintain a suitable vaccination schedule and use vaccines that are within their expiry date and stored correctly.

People 65 years and older, pregnant women, young children, individuals with cardiovascular or respiratory diseases, diabetes, weakened immune systems, and healthcare workers are at high risk of severe flu or exposure to pathogens, and they need to be particularly proactive. Young children from 6 months to under 9 years old require two doses in their first vaccination season; the first dose should be administered early to ensure the second dose is given according to recommended intervals. Individuals with a high fever or moderate to severe acute illness should inform medical staff to consider the appropriate vaccination time.

In your case, if your last flu shot was about one year ago or if you have not been vaccinated, you can get examined and vaccinated when eligible, without waiting specifically for april or october. If you were recently vaccinated, the doctor will refer to your vaccination history to schedule the next dose. Timely vaccination helps reduce the risk of contracting flu and, especially, the risk of severe progression, but it does not offer absolute protection.

Beyond vaccination, you should prevent illness by: washing hands regularly, covering your mouth when coughing or sneezing, limiting touching your eyes, nose, and mouth, and avoiding close contact with symptomatic individuals. If you experience high fever, shortness of breath, chest pain, disorientation, or prolonged symptoms, you need to seek medical attention instead of self-medicating at home.

Doctor Le Thi Minh Nguyet

Medical Manager, VNVC Vaccination System

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