Measles outbreak could be triggered in Hong Kong by small number of people who are not vaccinated, HKU professor says

A small proportion of people who are not effectively vaccinated against measles could trigger an outbreak of the highly contagious disease in Hong Kong, according to a medical expert.

The claim was made as the Japanese prefecture of Okinawa on Monday declared its measles outbreak over. Some 99 people were infected during the four-month outbreak, with about 5,500 tourists, including hundreds from Hong Kong, cancelling trips to the popular destination.

Professor Malik Peiris, chair of virology at the University of Hong Kong’s School of Public Health, said: “The measles vaccine is 95 per cent effective but there is still a small minority whose immunity may be weak or does not last long enough. Parents should make sure that their children are vaccinated against measles.”

The Centre for Health Protection urged anyone born before 1990, especially those not born in Hong Kong and who were unsure of their vaccine history, to get a dose ahead of their summer holiday.

Peiris blamed complacency by parents on the outbreak in Okinawa. Over the last 30 years, “the disease has been controlled and parents did not know what measles was as there had been no outbreak,” he said.

In 2015, the World Health Organisation verified that Japan had successfully eliminated measles.

Private clinics in Hong Kong have restocked since being inundated with calls from worried parents in April. A spokeswoman for MSD, known as Merck in the United States, said it had “significantly” increased its supply of the measles vaccine to meet demand.

The Department of Health only provides vaccines for one-year-olds and Primary One pupils at maternal and child health centres.

As of May this year, India had reported 8,510 confirmed and suspected measles cases to the WHO. This was followed by China (2,754), Malaysia (1,441), Thailand (1,317), Philippines (873) and Indonesia (567 cases). Hong Kong had reported seven cases, of which six were imported and the other was an expatriate who travelled to Thailand and returned to the city during the incubation period.