SINGAPORE: Babies aged between six and 11 months and who are travelling to countries with measles outbreaks or high measles incidence will need to get the measles, mumps and rubella (MMR) vaccine.
The dose, the first of two, should be given at least two weeks before the trip to reduce the risk of infection, as advised by the Communicable Diseases Agency (CDA) on Feb 13.
In a parliamentary written reply to Ng Shi Xuan (Sembawang GRC) on Wednesday (Feb 25), Health Minister Ong Ye Kung said that for long-term immunity, these infants should still complete the two-dose MMR vaccine series according to the National Childhood Immunisation Schedule.
In Singapore, the first dose is given at 12 months, and the second at 15 to 18 months.
Infectious diseases experts say that if the vaccine is given too early, such as to an infant under 12 months old, the protective effect of the MMR vaccine may not be long-lasting.
“If the MMR vaccination is given too early, some of the maternal antibodies (in the infants) will block the vaccine, rendering it less effective. Hence, they will need a follow-up vaccination very shortly thereafter,” said infectious diseases specialist Leong Hoe Nam. Maternal antibodies generally circulate in an infant for six to 12 months.
The measles virus is spread through air droplets and direct contact with nasal and throat secretions. Symptoms of measles include fever, cough, runny nose, sore throat and rashes.
There is no specific treatment, and most people recover in two to three weeks.
However, measles can lead to serious complications, including pneumonia and encephalitis – inflammation of the brain – especially in children below five years old.
In an earlier parliamentary written reply, Ong said measles vaccination coverage for children aged two has been about 93 per cent for both doses, and 97 per cent by age seven.
“In addition, seroprevalence survey data showed that 99 per cent of adult residents in Singapore have immunity against measles. This is above the measles herd immunity threshold of 95 per cent to prevent populationwide spread and protect those who are unable to receive the vaccination, such as infants under 12 months,” he said.
Seroprevalence studies use blood tests on samples to estimate true disease prevalence, including asymptomatic or undiagnosed cases, to help in public health planning.
While there is currently no community spread of measles here, Singapore remains vulnerable to imported cases, small pockets of unvaccinated individuals, and high travel volumes from measles outbreak areas.
Ong said the country’s high vaccination numbers, monitoring and prompt public health response help safeguard against measles becoming endemic.
He said there were 50 laboratory-confirmed measles cases between Jan 1, 2021, and Dec 31, 2025. Of these, three were tourists, and the rest were living in Singapore. Six cases were breakthrough infections in vaccinated individuals.
Infectious diseases experts said such breakthrough infections are rare.
Professor Paul Tambyah, past president of the Asia Pacific Society of Clinical Microbiology and Infection, told The Straits Times: “There are reports of people who had been partially vaccinated who get infected, but they generally do not go on to cause outbreaks. The reason is that the immune system is likely to kick in, even at a slower rate in partially vaccinated individuals, and the virus is unlikely to proliferate fast enough to cause an outbreak.”
Dr Leong added: “Measles immunity has been very robust after a live infection (or vaccination). It is only the very immunocompromised hosts who do get infected, and stay infected because their immunity cannot mount an adequate response.”
On Feb 17, CDA was notified of an 11-month-old girl infected with measles.
She was the first measles case in a pre-school child since CDA stepped up measures on Feb 6, and the fifth measles case involving an infant below the age of 12 months in 2026 – bringing Singapore’s total count in 2026 to 15 as at Feb 23.
Prof Tambyah said measles spreads extremely quickly among those who are unvaccinated and not previously exposed populations, and “vaccinating infants too early when their immune systems are not fully mature runs the risk of an inadequate response”.
He said, however, that if the adults around the babies in infant care centres are inoculated against measles, chances are, the babies will also be protected.
“The concept of cocooning vaccination has been used, for example, in protecting infants from whooping cough... The principle is that if you inoculate all the adults in the infant care centre, as well as family members, the infants who are not yet eligible for vaccination will be protected,” he said. - The Straits Times/ANN
