Why you should consider travel vaccinations even to places like Bali or Tokyo

A version of this article was originally published on CNA Lifestyle

Your tickets and accommodation are booked. Your luggage is packed. You’re all set to jet out of Singapore. But, wait: Have you had your jabs yet?

What’s the big deal, you ask? You’re only taking a short sojourn to Bangkok or Bali. Or yet another trip to Hong Kong and Japan. Is getting a vaccination necessary?

It’s not like you’re joining the BBC crew on a documentary-making expedition to some exotic location. You’re more concerned about getting ripped off at a hipster cafe than picking up Hepatitis, to be honest.

But there are actually still some risks involved, said Dr John Cheng, head of primary care and family physician at Healthway Medical, even if you’re heading into a city.

The higher the traveller traffic, the higher the possibility of contracting certain diseases. “Even in urbanised environments, there are risks of various diseases such as typhoid, tetanus and Hepatitis A,” he said.

The vaccinations you need may vary from region to region, even within the same country. “Take China, for instance. If you are visiting the smaller cities or rural parts, where there might be inadequate access to clean water, you may face the risk of contracting typhoid through the consumption of unclean food or water,” said Dr Cheng.



Yes, you were vaccinated as a baby and in primary school against tetanus, measles, rubella, mumps, diphtheria, whooping cough and polio. However, they may not be effective now. The tetanus vaccine, for instance, needs booster shots every 10 years after the age of 10 in order to work.

“The immunity fades over time, which means some vaccinations require booster shots or a revaccination. Boosters are doses of a vaccine after the initial immunisation course. They are given to help revive your immune system and to produce more antibodies, hence strengthening your immunity to that disease,” said Dr Cheng.

The Hepatitis B jab is now given to infants as part of the national vaccination programme. But if you were born before 1987, or if you grew up overseas, you may not be covered.

Depending on where you’re travelling to, you may be advised to get vaccinated against other diseases.

Travellers to China, India, Indonesia and Vietnam, for instance, are recommended to get jabs against Hepatitis A and B, influenza, Japanese encephalitis, rabies, typhoid and malaria.

Even if you have the standard list of travel vaccinations under your belt or skin, so to speak, it may not be sufficient.

For one, the possible diseases carried by travellers are unpredictable, said Dr Cheng. Two, new outbreaks in Zika, Sars and MERS-CoV would usually mean updates in the vaccinations used. “It is important to be kept up-to-date on your upcoming travel destination, and to speak to your doctor about the possible risks you may encounter,” said Dr Cheng.



So, you’ve decided to get vaccinated before boarding the plane. In general, some of the commonly recommended vaccinations are as follows, said Dr Cheng.


  • Doses required: One
  • Time taken for vaccine to take effect: Two weeks
  • Duration of effect: Six to 12 months

Hepatitis A

  • Doses required: Two (six months apart)
  • Time taken for vaccine to take effect: Two weeks
  • Duration of effect: Eight to 10 years

Hepatitis B

  • Doses required: Three (zero, one and six months apart)
  • Time taken for vaccine to take effect: Two to four weeks; maximum efficacy after third dose
  • Duration of effect: Eight to 10 years


  • Doses required: One
  • Time taken for vaccine to take effect: Two weeks
  • Duration of effect: Three years


  • Doses required: One
  • Time taken for vaccine to take effect: Two weeks
  • Duration of effect: 10 years



If you’re pregnant and wondering if you should get vaccinated, consult your doctor. Generally, vaccinations that use inactivated viruses such as the influenza vaccine and the Hepatitis B vaccine can be given during pregnancy, said Dr Cheng.

But mothers-to-be should steer clear of vaccines that have live viruses, including those for measles, mumps, rubella and chicken pox, he said.

“Though there is no evidence of any live vaccine causing a birth defect, the theoretical possibility of foetal infection does exist,” said Dr Cheng. “These vaccines are made from live viruses and could potentially infect the mother and her unborn baby with the disease. Thus, such vaccinations should be delayed until after delivery.”

If you can’t remember what disease you’ve had the jab for, or if you need booster shots, your doctor can conduct a blood test to check your antibody levels and confirm immunity.

“Generally, it is safe to receive an extra dose of the same vaccination again even if you are previously vaccinated,” said Dr Cheng, who also suggested gathering the following information before stepping into the doctor’s office:

  • Which part of the country you are travelling to
  • The duration of your trip
  • What activities you might do (for instance, hiking, swimming, camping)

Your body takes time to produce antibodies and build immunity; a process that generally takes about two weeks after the injection is administered, said Dr Cheng.

To make it in time for your trip, consult your doctor at least four to six weeks before you leave the country, he advised. This period also includes the time you need to recover from any side effects such as fever, fatigue and soreness in the injected area.