From the United States to Asia to Europe, the highly contagious, sometimes fatal, but preventable disease of measles is resurging among adult and child populations. The number of cases in Hong Kong this year, at least 30, is more than four times higher than the annual figures for the past four years. Officials expect the number to rise . Even in places where it had been eliminated, or nearly so, such as this city, measles has often reappeared through infected travellers and spread among people not fully protected by vaccination. Two contagion issues set this city apart. The airport seems to be an infection hub, with a number of cases involving airline and airport personnel , and many originating overseas. And, according to the Centre for Health Protection, a Cathay Pacific pilot who developed a rash and a temperature on March 12 flew seven legs between the city and Singapore and Bangkok from the 13th to the 16th, before being taken to Princess Margaret Hospital for treatment for measles. It is not clear whether the pilot broke rules relating to fitness for duties, or whether medical opinion was sought on flying during the contagious stage of measles. In any case, lawmaker Ben Chan Han-pan, chairman of the Legislative Council’s transport panel, may be right to say the incident exposes “major loopholes” in the system. That issue aside, the authorities have responded to the outbreak with a change of vaccination policy for children, who will receive their second vaccination at 18 months instead of six years from next year, and advice to agents for domestic helpers to see that they are vaccinated before arriving here from the Philippines, which has reported 23,000 measles cases this year. Supplies of vaccine to private clinics and or airport staff have been stepped up. Hong Kong is fortunate that enlightened vaccination policies have left it with what health authorities describe as a relatively good level of protection, as high as 96 per cent after two doses of a vaccine, compared with 55 per cent in the Philippines. The local outbreak is a reminder that even in the 21st century, health officials can never relax efforts to ensure the highest possible vaccination rates in the face of fears and misinformation about vaccination spread on the internet that have no scientific basis.