How to protect yourself during flu season? A complete guide to vaccines, personal hygiene, and lifestyle habits.

Seasonal influenza (flu) is an acute respiratory illness caused by the influenza virus. Many people believe that the flu only circulates in winter, but in Hong Kong...Influenza cases occur year-round, but are generally more prevalent from January to March/April and in July and August.(Hong Kong Centre for Health Protection). In other words, protection is not something that "only needs to be done in winter," but rather a continuous habit throughout the entire flu season.

One effective way to prevent influenza is...Get a flu shot every yearHowever, vaccines are not the only factor. Good personal hygiene, lifestyle habits, and environmental hygiene are also essential, along with vaccines.Complement each otherThe Centre for Health Protection also clearly states that even after vaccination, it is still important to maintain good personal and environmental hygiene habits, pay attention to a balanced diet, exercise regularly, get enough rest, and not smoke.

The following is a summary of information other than vaccines.Seven details of lifeIt also provides information on which claims are supported by official sources or research, and which need to be revised, so that you can grasp the truly feasible practices.

What is influenza? Flu season and symptoms in Hong Kong.

Influenza virus is mainly transmitted through patientsTransmission occurs through droplets produced when coughing, sneezing, or talking.It can also be transmitted through direct contact with the patient's secretions. Known seasonal influenza viruses that can infect humans include type A, type B, and type C; currently, the seasonal influenza A circulating between humans is mainly of two subtypes: type A (H1N1) pdm09 and type A (H3N2).

Symptoms and incubation period

Healthy people who contract the flu usually experience symptoms within 30 days.It will heal on its own within a few days to two weeks.Common symptoms include fever, cough, sore throat, runny nose, muscle and joint pain, fatigue, and headache; vomiting and diarrhea may also occur. The incubation period is generally about [time missing].One to four days(Hong Kong Centre for Health Protection).

It is important to note that influenza is not the same as the common cold. The symptoms of the common cold are usually milder, mainly nasal congestion and runny nose; influenza, on the other hand, has a more rapid onset, with more pronounced fever and body aches, and can potentially lead to complications.

Transmission routes and environmental factors

Besides droplets and contact, environmental factors also influence transmission:crowded places with poor air circulationViruses tend to accumulate and spread more easily in such environments; conversely, maintaining good indoor air circulation and frequently cleaning frequently touched surfaces can reduce the risk. This is one of the key points discussed later in this article.

Who belongs to the high-risk group?

Most healthy people recover from the flu on their own, but some individuals have a significantly higher chance of developing severe symptoms once infected. The Centre for Health Protection identifies high-risk individuals as follows:

• Senior citizens(Especially those 65 years or older)
• Children under five years old
• Pregnant women
• People with chronic illnesses(For example, those with cardiovascular disease, lung disease, liver disease, metabolic disease, or kidney disease, as well as those with weakened immune systems)
• Body Mass Index (BMI) 30 or aboveObesity is considered an independent risk factor for flu complications in individuals.

These individuals may experience complications after infection, includingPneumonia, sepsis, encephalitis, myocarditis, and in severe cases, even death.Therefore, if you or your family members belong to the above groups, in addition to getting vaccinated, you should seek medical attention as soon as possible if you develop respiratory infection symptoms.

First line of defense: Annual flu vaccination

Getting vaccinated against seasonal influenza is an effective way to prevent influenza and its complications, and can also reduce hospitalizations and deaths due to influenza. Given that healthy individuals can also contract severe influenza, the Centre for Health Protection recommends—Except for individuals with known contraindications, all individuals aged 6 months or older should receive an influenza vaccine annually.To protect personal health.

Who should be vaccinated and who should be vaccinated first?

All individuals 6 months or older are suitable for annual vaccination. In addition, the Hong Kong Scientific Committee on Vaccine-Preventable Diseases also recommends the following individuals...Priority vaccinationThe following individuals are eligible for vaccination: healthcare workers, individuals aged 50 or older, individuals aged 18 to 49 with chronic health conditions, pregnant women, children and adolescents aged 6 months to under 18 years, residents of nursing homes, poultry industry workers, and those engaged in pig farming and slaughtering. Members of the public may consult their family doctor for recommendations on vaccination.

When to get vaccinated and how strong is the protection?

Committee RecommendationsOctober to NovemberThe optimal time for vaccination is [time]. This is because the body needs approximately [time period] after vaccination to [time period].Two weeksAntibodies are produced, so vaccination should be given at least two weeks before the main flu season to ensure adequate protection during the flu season; even if vaccination is not given during the recommended period, it is still recommended to get vaccinated as soon as possible (Hong Kong Centre for Health Protection).

Regarding protective efficacy: Literature indicates that if the vaccine's antigen matches the prevalent virus type, the influenza vaccine can...It reduces the risk of influenza in the overall population by 401 TP4T to 601 TP4T; for people aged 65 or younger, it can reduce the risk by 701 TP4T to 901 TP4T.The influenza virus can spawn new strains from time to time, so the vaccine composition is updated every year, and annual vaccination is required.

Several common concerns can be clarified:Neither inactivated influenza vaccines nor recombinant influenza vaccines will cause influenza.It is safe for pregnant women to receive inactivated influenza vaccines. People who are sensitive to eggs can generally be vaccinated safely, but those who have had a severe allergic reaction to eggs should be vaccinated by professional medical personnel in an appropriate medical setting.

Vaccines and lifestyle habits complement each other.

Vaccination does not mean you can let your guard down. The Centre for Health Protection clearly states in its FAQs on vaccination that it takes about two weeks for the body to develop antibodies after vaccination, and reminds those who have already been vaccinated.It is still important to maintain good personal and environmental hygiene habits, pay attention to a balanced diet, exercise regularly, get enough rest, and not smoke.。

In other words, vaccines and lifestyle habits are not an either-or choice, but rather two complementary layers of protection. The following seven lifestyle details are the specific contents of this second layer of protection.

Seven lifestyle details to reduce the risk of virus infection

1. Dry your hands thoroughly after washing to reduce the re-adhesion of pathogens.

Handwashing is key to preventing cross-infection, but the method is equally important. The Centre for Health Protection recommends:First, wet your hands with water, add lye solution, and rub your hands together for at least 20 seconds.(Covering the palms, backs of hands, between fingers, thumbs, fingertips, and wrists), then rinse thoroughly with water.Dry your hands thoroughly with paper towels or a clean towel.After drying your hands, wrap the faucet with a paper towel before turning it off to avoid touching the faucet again with your freshly washed hands.

Why emphasize "drying"? BecauseWet hands are more likely to re-adhere to pathogens in the environment.Drying is an integral part of the handwashing process, not an optional finishing touch. If hands are not visibly dirty, using a hand sanitizer containing 70% to 80% alcohol is an effective method; however, if hands are visibly dirty or contaminated with secretions, they must be washed with soap and water.

2. Use serving chopsticks and spoons when dining together to reduce cross-contamination.

Using serving chopsticks and spoons when dining with family and friends is a good food hygiene habit and can reduce the risk of foodborne illness.Cross-contamination of saliva and tablewareThis increases the chance of pathogen transmission. The Centre for Health Protection, in its advice on dining out, also emphasizes separating raw and cooked foods; and regarding respiratory and contact-transmitted diseases, it also reminds the public...Do not share personal items such as towels and tableware with others.。

It should be noted that influenza mainly occurs through...DropletsThe use of serving chopsticks is not specifically designed for the spread of influenza, but rather is an integral part of overall food hygiene. It is more accurate to view serving chopsticks as a good habit of "taking an extra step"—it complements measures such as handwashing and wearing masks.

3. Replenish key nutrients to support the immune system.

Many natural foods help maintain the body's resistance. The following two types of nutrients are closely related to immune function:

• Vitamin CHelpfulMaintaining the normal functioning of the immune systemIt also helps the body absorb iron from plant-based foods. Citrus fruits (oranges, lemons, grapefruits), red bell peppers, green bell peppers, kiwis, and broccoli are rich in vitamin C. Fresh fruits and vegetables should be bought and eaten as soon as possible, and prolonged soaking and high-temperature cooking should be avoided to minimize vitamin C loss (NIH Office of Dietary Supplements, National Institutes of Health).
• Vitamin A and caroteneVitamin AImmune system and normal growth and developmentIt is extremely important and helps maintain the normal structure of epithelial tissues (mucous membranes) such as the respiratory tract. Orange-yellow and dark green fruits and vegetables such as carrots, papayas, pumpkins, spinach, and mangoes are rich in beta-carotene, which the human body can convert into vitamin A (NIH ODS). Long-term vitamin A deficiency is associated with an increased risk of respiratory diseases and infections, demonstrating its fundamental role in the body's defense.

Regarding whether supplementing with high doses of vitamin C can prevent colds, research results are not entirely consistent—a meta-analysis shows that for generally healthy individuals, regular supplementation may not significantly reduce the incidence of colds, but it may help.Slightly shorten the course of the disease(Hemilä and Chalker, Cochrane Systematic Review, 2013). Therefore, the practically feasible approach remains...The foundation is a balanced diet with enough fruits and vegetables every day.Nutrient supplements should be considered as supplements, not as replacements for natural foods.

4. Maintain a relaxed state of mind and face long-term stress squarely.

There is indeed a link between psychological stress and the immune system. A meta-analysis encompassing over 300 studies and summarizing 30 years of literature found that:Short-term stress (such as exams) tends to suppress some immune functions, while long-term, chronic stress is associated with the suppression of both cellular and humoral immunity.(Segerstrom and Miller, Psychological Bulletin, 2004).

This doesn't mean "you'll catch a cold if you're in a bad mood," but rather it's a reminder.The ongoing pressure deserves to be acknowledged.Practical daily practices include listening to music, doing yoga, taking walks, practicing deep breathing, talking to someone, and maintaining a regular sleep schedule. Furthermore, chronic stress can affect sleep, and insufficient sleep can in turn exacerbate stress, creating a vicious cycle—therefore, addressing both stress reduction and sleep together often yields better results.

5. Regular aerobic exercise can help reduce upper respiratory tract infections.

Regular exercise not only promotes blood circulation and relieves stress, but also helps maintain the body's defenses. A study that tracked 1,002 adults for twelve weeks found that:People who engaged in aerobic exercise 5 days or more per week experienced approximately 431 TP4T fewer days with upper respiratory tract infection (URTI) symptoms compared to those who rarely exercised; the group with higher fitness also experienced a reduction of approximately 461 TP4T, and symptom severity decreased by approximately 321 TP4T to 411 TP4T.(Nieman et al., British Journal of Sports Medicine, 2011).

Regarding exercise levels, the World Health Organization recommends that adults...Engage in 150 to 300 minutes of moderate-intensity aerobic exercise (or 75 to 150 minutes of vigorous-intensity aerobic exercise) per week, and perform muscle-strengthening activities at least two days per week.Swimming, running, cycling, and brisk walking are all common choices. It's important to pay attention to the word "moderate": after excessively strenuous exercise, the body will be in a more susceptible state to infection for a short period of time. Therefore, it is better to proceed gradually and within one's ability than to overexert oneself all at once.

6. Ensure sufficient sleep to allow the immune system to function properly.

Sleep is closely related to immunity. A classic study involved 153 healthy adults who recorded their sleep for 14 consecutive days, followed by controlled exposure to rhinovirus. The results showed that:People who sleep less than 7 hours per night on average are 2.94 times more likely to catch a cold than those who sleep 8 hours or more; those with a sleep efficiency lower than 92% are up to 5.50 times more likely.(Cohen et al., Archives of Internal Medicine, 2009).

It is generally recommended that adults sleep every night.7 to 9 hoursTo improve sleep, keep these points in mind: maintain a regular sleep schedule, reduce screen time before bed, avoid eating large meals or consuming caffeine before bed, and keep your bedroom cool and quiet. If you suffer from chronic insomnia or poor sleep quality, consult a doctor.

7. Avoid crowded places and ensure good air circulation.

During flu season, the virus is inCrowded public places with poor ventilationIt is relatively easy to spread. The Centre for Health Protection recommends that people avoid going to such places as much as possible; high-risk individuals (such as those with pre-existing health conditions or weakened immune systems) may consider wearing surgical masks when using public transport or in crowded places.

If you need to stay at home for an extended period of time, you should pay attention to your home environment:Regularly open windows to allow air circulation, and periodically clean and disinfect frequently touched surfaces.In addition, anyone experiencing fever or respiratory infection symptoms should wear a surgical mask to reduce the risk of spreading the virus to others.

Home and Environmental Hygiene: Ventilation and Disinfection

The Centre for Health Protection offers the following specific practices for environmental hygiene, which are worth implementing at home:

• Disinfect frequently touched surfacesShared items such as furniture, toys, door handles, and handrails can be used.Dilute household bleach 1:99Disinfect with 1 part bleach containing 5.251T sodium hypochlorite and 99 parts water. After 15 to 30 minutes, rinse with water and dry. Metal surfaces can be cleaned and disinfected with 701T alcohol.
• Cleaning respiratory secretions and other wasteFirst, use a highly absorbent disposable wipe to clean visible dirt, then use...Dilute household bleach 1:49Disinfect the contaminated area and surrounding area with 1 part bleach and 49 parts water. After 15 to 30 minutes, rinse with water and dry.
• Keep indoor air circulatingOpen the windows and clean the air conditioner's dust filter frequently to keep the ventilation equipment in good working order.

These practices may seem trivial, but they are crucial for cutting off "contact transmission" and reducing the concentration of the virus in the environment. For details on hand hygiene in supermarkets, public places, and other similar environments, please refer to the information on this website.Hand hygiene and infection prevention in public placesOne article.

What to do if symptoms appear? Seeking medical attention and care.

Most people recover from the flu on their own, during which time...Get plenty of rest, drink plenty of water, and avoid going to work or school.To avoid infecting others, wear a mask. However, if symptoms persist or worsen, seek medical attention as soon as possible.

You should seek medical attention as soon as possible in the following situations:

• Symptoms do not improve or gradually worsen
• Symptoms include difficulty breathing, chest pain, persistent high fever, altered mental status, or severe dehydration.
• Those who belong to high-risk groups (elderly, young children, pregnant women, patients with chronic diseases, and those with low immunity)

There are two points to be clear about regarding medication:Antiviral drugs must be prescribed by a doctor.Early use can alleviate symptoms and shorten the duration of illness, but it is not advisable to purchase and take it on your own;Antibiotics are only effective against bacterial infections and not against influenza viruses.Therefore, antibiotics cannot cure the flu or speed up recovery. If critical symptoms occur (such as severe difficulty breathing or loss of consciousness), call [phone number] immediately. 999 Help needed.

Frequently Asked Questions

What are the differences between influenza and the common cold?

The two are caused by different viruses. Common cold symptoms are usually milder, mainly consisting of nasal congestion, runny nose, and sore throat; influenza, on the other hand, has a more rapid onset, with more pronounced systemic symptoms such as fever, muscle and joint pain, and fatigue, and is more likely to lead to complications such as pneumonia and encephalitis. Because the symptoms are similar, a doctor should make a diagnosis if the symptoms are severe or persistent.

After receiving the flu vaccine, are there any other lifestyle habits I need to follow?

Yes, it is necessary. The Centre for Health Protection clearly states that even after vaccination, it is still important to maintain good personal and environmental hygiene habits, a balanced diet, regular exercise, sufficient rest, and not to smoke. Vaccines and lifestyle habits are two complementary layers of protection, not an either-or choice.

Does not drying your hands after washing them really have any negative effects?

Yes. Damp hands are more likely to re-adhere to pathogens in the environment, so "thoroughly drying" is part of the handwashing process. It is recommended to dry hands with paper towels or a clean towel, and to wrap the faucet with a paper towel before turning it off to avoid secondary contamination.

Can using serving chopsticks really prevent the flu?

Using serving chopsticks is part of food hygiene, reducing the chance of cross-contamination through saliva and utensils. However, it's important to understand that influenza is primarily spread through droplets, and serving chopsticks are not specifically designed for influenza; rather, they are a holistic protective habit that complements measures such as handwashing. When dining out, separating raw and cooked foods and avoiding sharing utensils are practices worth maintaining.

Can Vitamin C really prevent the flu?

Vitamin C helps maintain a healthy immune system, and getting enough from fruits and vegetables is fundamental to maintaining immunity. Regarding whether high-dose supplementation can prevent colds, research results are not entirely consistent; a comprehensive analysis shows that regular supplementation may slightly shorten the duration of illness, but for generally healthy individuals, it may not significantly reduce the incidence of colds. Therefore, a balanced diet rich in fruits and vegetables is more practical.

Is seven hours of sleep enough?

It is generally recommended that adults sleep 7 to 9 hours per night. Studies also show that...Sleep duration is just as important as sleep quality.—In addition to the number of hours, low sleep efficiency (i.e., long hours spent lying down but short actual sleep duration) is also associated with a higher risk of catching a cold. Maintaining a regular sleep schedule and improving the sleep environment are more meaningful than simply "reaching the required number of hours".

Is more exercise always better?

No. Regular, moderate exercise helps maintain immunity, but excessively strenuous exercise can temporarily put the body in a more susceptible state to infection. It is recommended to gradually increase the intensity to 150 to 300 minutes of moderate-intensity aerobic exercise per week, as recommended by the World Health Organization, and combine it with at least two days of muscle-strengthening activities per week.

Can getting a flu vaccine cause you to catch the flu?

No. Inactivated influenza vaccines contain dead viruses, while recombinant influenza vaccines contain viral surface antigens; neither will cause influenza. Live attenuated influenza vaccines contain weakened viruses and will not cause influenza in individuals with normal immune function. Common side effects include pain and swelling at the injection site, or brief fever and muscle pain, which are usually mild and short-lived.

When should you seek medical attention?

If symptoms persist or worsen, or if you experience difficulty breathing, chest pain, persistent high fever, altered mental status, or severe dehydration, seek medical attention immediately. If you belong to a high-risk group (elderly, young children, pregnant women, those with chronic illnesses, or those with weakened immune systems), you should also seek medical attention promptly if you develop respiratory infection symptoms. In case of emergency, call 999 immediately.

What precautions should pregnant women, children, and the elderly take?

These three groups are considered high-risk for influenza and have a higher chance of developing complications after infection. Annual influenza vaccination is recommended (pregnant women can receive the inactivated influenza vaccine). In addition to the lifestyle details mentioned above, seek medical attention promptly if symptoms appear and avoid self-medication. For vaccination arrangements or personalized advice, consult your family doctor.

Data Sources and Health Disclaimer

Source:

• Centre for Health Protection, Department of Health, Hong Kong.Seasonal influenza> (Pathogen, symptoms, transmission routes, incubation period, high-risk groups and complications, prevention methods).
• Centre for Health Protection, Department of Health, Hong Kong.Frequently Asked Questions about Seasonal Influenza Vaccination in Hong Kong> (Target population and priority groups for vaccination, timing of vaccination, protective efficacy, vaccine safety, and the need to maintain good lifestyle habits after vaccination).
• Centre for Health Protection, Department of Health, Hong Kong.Seasonal Influenza Special Page> (Influenza surveillance and vaccination program information).
• Centre for Health Protection, Department of Health, Hong Kong.Proper handwashing> (The importance of hand hygiene in preventing the spread of disease).
• Centre for Health Protection, Department of Health, Hong Kong.Correct handwashing method〉、〈Five steps to proper handwashing> (Rub your hands for at least 20 seconds, rinse and dry them thoroughly with paper towels, then turn off the tap with the paper towels).
• Centre for Health Protection, Department of Health, Hong Kong.Use masks correctly> (Maintain hand hygiene before and after wearing a mask).
• Centre for Health Protection, Department of Health, Hong Kong.Severe cases of enterovirus infection in children> (Do not share personal items such as towels and utensils with others; keep the air circulating).
• Centre for Health Protection, Department of Health, Hong Kong.Investigating suspected food poisoning cases> (Use two sets of chopsticks and cooking utensils to handle raw and cooked food separately).
• The National Institutes of Health's Office of Dietary Supplements (NIH ODS)Vitamin C — Fact Sheet for Consumers(Vitamin C helps the immune system function properly; food sources; research findings on the common cold).
• The National Institutes of Health's Office of Dietary Supplements (NIH ODS)Vitamin A and Carotenoids — Fact Sheet for Consumers(The important role of vitamin A in the immune system and epithelial tissues, beta-carotene and its food sources).
• Cohen S, Doyle WJ, Alper CM, Janicki-Deverts D, Turner RB. Sleep habits and susceptibility to the common cold. Arch Intern Med. 2009. PMID 19139325。
• Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013. PMID 23440782。
• Segerstrom SC, Miller GE. Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry. Psychol Bull. 2004. PMID 15250815。
• Nieman DC, Henson DA, Austin MD, Sha W. Upper respiratory tract infection is reduced in physically fit and active adults. Br J Sports Med. 2011. PMID 21041243。

Health Disclaimer:This article is for general health and nutrition information only and should not replace professional medical diagnosis, treatment, or individual advice. Everyone's health condition and disease risk are different; vaccination, medication, and lifestyle adjustments should be determined on an individual basis and based on assessment by a healthcare professional. If you have a chronic illness, are pregnant, breastfeeding, elderly, infant, young child, or have a weakened immune system, or are currently taking prescription medications, consult your doctor before vaccination or lifestyle adjustments. If you experience emergency symptoms such as difficulty breathing, chest pain, persistent high fever, or confusion, call 999 immediately for help; if symptoms persist or worsen, seek medical attention as soon as possible.