askST: What are Singapore’s enhanced measures to contain the risk of measles infections?

SINGAPORE – The Communicable Diseases Agency (CDA) stepped up precautionary measures against measles on Feb 6 to prevent community transmission of the highly contagious virus.

The Straits Times looks at the measles situation in Singapore and the measures aimed at tackling the increase in cases.

Q: What is the situation in Singapore?

A: Singapore recorded 11 measles cases within the first month of 2026, the same number as for the whole of 2024. It is a jump from the two cases in January 2025.

Health Minister Ong Ye Kung said 99 per cent of adults in Singapore have immunity against measles.

However, the risk of imported cases continues to be a concern, given Singapore’s travel hub status, where both foreigners entering the country and returning residents who were not fully vaccinated could bring in the virus.

Q: If we have herd immunity, why should we still be worried about cases?

A: Senior Minister of State for Health Koh Poh Koon said there are still some people vulnerable to measles infection, such as those who are immunocompromised.

Infants below 12 months old are also vulnerable, and this is the group which Mr Ong said the authorities are “especially worried about” as they cannot be vaccinated with the measles, mumps and rubella (MMR) vaccine yet. If infected, they may face serious complications, including pneumonia and encephalitis, the inflammation of the brain.

Q: Who needs to take the MMR vaccine?

A: Children are recommended to take two doses of the vaccine, at the ages of 12 months and 15 months. Proof of vaccination is required for admission to pre-school and primary school.

Adults who have not been previously vaccinated or lack evidence of past infection or immunity are also recommended to take two doses at any time in their lifetime, according to guidelines under the National Adult Immunisation Schedule.

The Manpower Ministry has mandated that from Sept 1, 2025, employers of migrant domestic workers must ensure that their worker has immunity against measles if their household has a child below seven years old who is not fully vaccinated.

The Health Ministry has also mandated that foreign-born children must submit diphtheria and measles vaccination documents as a prerequisite to apply for long-term immigration passes, since Feb 1, 2019.

Q: Does vaccination give me lifelong immunity and prevent me from transmitting the virus to others?

A: Taking the MMR vaccine is safe, highly effective and confers long-term immunity, said Associate Professor Lim Poh Lian, CDA’s group director of the communicable diseases programmes. She added that infections after vaccination – known as breakthrough infections – are very rare.

In 2019, then Health Minister Gan Kim Yong said in Parliament that up to 3 per cent of those vaccinated may not have effective protection.

Based on information on the US Centers for Disease Control and Prevention (CDC) website, breakthrough infections are more common when there is intense or prolonged exposure to an infected person.

Nevertheless, the CDC said there are still benefits to vaccination – such individuals are more likely to have milder illness, less likely to develop complications from infection, and less likely to spread the virus to others.

Q: What are CDA’s enhanced public health measures?

A: Confirmed cases will be isolated either in hospitals or at home until they are no longer infectious. Random video-call checks will be conducted for those on home isolation. Contact tracing will be conducted for all confirmed cases.

High-risk close contacts, such as infants, non-immune pregnant women, and immunocompromised individuals, will be offered post-exposure prophylaxis (PEP), which refers to treatments to reduce the risk of the virus successfully establishing itself within the body.

PEP treatments can be either the MMR vaccine, or immunoglobulin for those who cannot be vaccinated due to medical reasons.

Non-immune close contacts will be quarantined at home for up to 21 days. Random video-call checks will be conducted. The quarantine will end earlier for those who complete their vaccinations, have PEP administered or are tested to be immune during quarantine.

Those who work in high-risk settings, such as hospitals, or infant and childcare centres, will not be offered an earlier end to their quarantine and have to be on hospitalisation leave until 21 days after their exposure to the virus.

Those who fail to comply with home isolation or quarantine orders may be liable to imprisonment and/or a fine upon conviction.

Casual, non-close contacts are advised to monitor their health, and seek medical care if they develop symptoms.

Q: Who are the 11 local cases?

A: The cases were all not fully vaccinated, and include three infants under 12 months old. Among the 11 cases, one is a tourist, while the remaining 10 live in Singapore. Seven of the cases had travelled overseas recently.

CDA did not provide additional information such as their ages or travel history outside and within Singapore, citing patient confidentiality.