askST: What should we consider before travelling and feasting this holiday season?

SINGAPORE – With the year-end holiday season in full swing, the Communicable Diseases Agency (CDA) has advised travellers on essential vaccinations, food safety and infection prevention.

Associate Professor Lim Poh Lian, group director of communicable diseases programmes at CDA, said Singapore residents have been infected with communicable diseases while abroad.

In 2024, five Singapore residents caught malaria and 14 had typhoid, with infection likely from their overseas travel, Prof Lim said.

These diseases can often be prevented with vaccines and medication taken before travelling.

Here, The Straits Times addresses key questions about staying healthy while overseas.

Q: Which vaccines are most important for year-end travel?

A: Prof Lim advises travellers to get the Northern Hemisphere flu vaccine as many people will encounter cold climates and crowded airports.

In addition, the pneumococcal vaccine is also recommended for healthy adults aged 65 and above, as well as for those under 65 with certain chronic medical conditions such as liver, kidney, heart or lung disease and diabetes. 

Q: Why is vaccination so important for the elderly traveller?

A: As people age, their immunity decreases. This might make diseases like the flu, which might cause only a few days of fever and misery in a 40-year-old, much more serious for someone who is 75 or 80.

In the elderly, diseases like the flu can destabilise existing medical conditions. “So if they are vomiting, have diarrhoea and are dehydrated, and taking diabetes medicines, they could end up with kidney failure, et cetera,” said Prof Lim.

With respiratory infections being prevalent this season, wearing a mask is a good way to protect against things like the common cold rhinovirus, for which there are no vaccines, she added. 

Q: Which vaccines are needed before travelling to developing countries?

A: Travellers heading to developing countries should ensure that they are vaccinated against food- and water-borne diseases like hepatitis A and typhoid fever.

Certain vaccines, like the hepatitis A vaccine, require two doses. The first dose provides immediate protection for your trip, while the second dose, given six months later, ensures long-term immunity.

Q: Are there special precautions for those going on the umrah this year end?

A: The Middle East respiratory syndrome (MERS) is still a concern, particularly for those who have been in contact with camels. Additionally, avian influenza remains a global concern.

Avoid exposure to live animals and poultry whenever possible. Should contact occur, wash hands thoroughly, said Prof Lim.

Q: Should travellers be concerned about yellow fever?

A: Yellow fever is a vaccine-preventable mosquito-borne viral disease. While Singapore is free from it, yellow fever vaccination is mandatory for those going to certain countries with risk of transmission.

Currently, African countries such as Kenya, Nigeria and Uganda, and Latin American countries such as Brazil and Colombia are classified as high-risk for yellow fever outbreaks.

The full list of high-risk countries is available on the CDA, Ministry of Health or Ministry of Foreign Affairs website, said Prof Lim. Failure to get the vaccine before returning to Singapore may result in quarantine.

Just in November, the CDA had said that Singapore

has to do a lot more to prevent the potential introduction and spread of yellow fever here

.

Q: How far in advance should I get my pre-travel vaccines?

A: Generally, people should schedule their pre-travel consultations four to six weeks before travelling because it takes one to two weeks for the protective immunity of vaccines to kick in, and some vaccines require more than one dose, Prof Lim said. 

Even if you consider vaccination just before travelling, some protection is always better than none, she said.

Q: Is it safe to get multiple vaccines at once?

A: It is perfectly fine to receive several vaccines simultaneously, Prof Lim said.

Q: What is the most common mistake travellers make regarding food and drinks?

A: Prof Lim, who is also the head of Tan Tock Seng Hospital’s Travellers’ Health and Vaccination Clinic, recommends that travellers avoid consuming high-risk items like ice and raw food if they want to lower the risk of food poisoning.

“If you don’t dare to drink the tap water, you should not be drinking frozen tap water,” she said. 

To illustrate that the quantity of bacteria present is key to the severity of disease, she recounted an incident in Peru, where she had a taste of ceviche, the local raw fish speciality, which an Australian colleague had ordered. 

She was fine, but her colleague suffered three days of vomiting.

Q: What should I take note of if I contract traveller’s diarrhoea?

A: The primary concern is dehydration. Drink lots of fluids that contain a little bit of salt or sugar, said Prof Lim.

“You can’t just drink pure water if you’re having diarrhoea, so things like chicken soup, fruit juice, something with a bit of sugar, a bit of salt would help. There are also oral dehydration salts,” she said. 

Seek medical care if you are showing signs of severe dehydration such as dizziness, or if your diarrhoea persists.

Q: What is the ‘temperature danger zone’ for food?

A: Ms Lalitha Kurupatham, CDA’s food and vector borne division director, said that bacteria multiply rapidly in temperatures between 5 and 60 deg C, increasing the risk of food poisoning.

Keep cold food below 5 deg C, and hot food above 60 deg C. If you have hot food that you intend to reheat and eat later, you must chill it below 5 deg C within four hours, she said.

Q: Can I reheat my food multiple times?

A: Do it once. Reheating food that has remained in the temperature danger zone for an extended period to a piping hot level is insufficient to eliminate all bacteria because some toxins produced by the bacteria are heat-stable and will not be destroyed, Ms Lalitha said.

Q: Why can’t I defrost food at room temperature?

A: Defrosting food at room temperature in Singapore would expose the food to the temperature danger zone for too long.

Instead, Ms Lalitha advised, defrost in the chiller, in the microwave oven using the defrost setting, or in a sealed leakproof bag placed in an ice bath in the sink.

Q: What precautions should I take when hosting elderly friends or relatives this holiday season?

A: Do not prepare food for them if you are unwell to reduce the risk of spreading diseases. Do not serve raw food like oysters. Shellfish filter large amounts of water to feed and in the process absorb harmful pathogens and other substances.