Singapore’s measles cases reach six-year high, three vaccinated cases among 40 infections

Both figures are above the 95 per cent herd immunity threshold needed to prevent population-wide spread and protect those unable to be vaccinated, such as infants under 12 months, MOH said.

BREAKTHROUGH INFECTIONS RARE

Breakthrough infections among vaccinated individuals remain uncommon despite the increase, CDA and experts said. 

The MMR vaccine’s efficacy has historically exceeded 95 per cent, and is about 97 per cent effective after two doses, with vaccinated individuals generally developing milder illness and fewer complications than the unvaccinated.

Professor Paul Tambyah, past president of the Asia Pacific Society for Clinical Microbiology and Infection, said factors such as underlying medical conditions or vaccine handling may contribute in the rare instances where vaccinated individuals become infected.

CDA said Singapore should continue to expect sporadic cases and small clusters, given its position as a major travel hub amid rising measles activity globally and regionally.

The agency introduced tighter measures in February, including mandatory isolation for measles cases, contact tracing for all cases and quarantine for some close contacts, after detecting a rise in infections.

Measures were stepped up further a month later after more infections were reported. This included barring all suspect measles cases in high-risk settings from returning to school or work until they test negative.

CDA advised older children and adults – particularly those travelling to countries experiencing outbreaks – to ensure they have received two doses of the MMR vaccine. Infants aged six to 11 months travelling to affected countries should seek medical advice about an early dose at least two weeks before departure.