Infants too young for vaccination infected in Australian measles outbreak

Two babies, aged 8 and 11 months, have been infected in a rare outbreak of measles in Australia as the highly contagious disease makes a comeback in East Asia and the Pacific.

Health authorities in New South Wales state said the infants likely caught the disease in public places.

They are too young to be vaccinated, Vicky Sheppeard, NSW Health’s director of communicable diseases, told CNN. The standard vaccination schedule in Australia starts at 12 months. Infants lose their maternal immunity by about 6 months of age, so are vulnerable for around another six months.

NSW Health said the younger child likely became infected in the central Haymarket area of Sydney between the 26th and 30th of March, while the 11-month-old is believed to have become infected in the northern suburban Eastwood area between the 23rd and 30th of March.

Sheppeard said the locations “do not pose an ongoing risk” of infection but anyone who may be susceptible to the disease should contact a doctor. The state has seen 23 confirmed cases of measles so far this year.

“The local public health units are working directly with medical practices and hospitals to follow up other patients present at the same time as the infants, and offer preventive treatment as appropriate,” she said.

If people “develop symptoms, please call ahead to your GP to ensure you do not wait in the waiting room with other patients,” she added.

Sheppeard told CNN that people who do not realize they are unvaccinated — those born after a national vaccination program began in 1966 but before a national registry was established — can pose a problem since their families may have missed “one or two doses” in the program.

The state provides free shots for people born after 1966 if they lack sufficient documentation from previous vaccinations, she said.

“The measles-mumps-rubella (MMR) vaccine is safe and effective protection against measles. It’s free for anyone born during or after 1966 who hasn’t already had two doses. If you’re unsure whether you’ve had two doses, it’s safe to have another.”

Worrying trends

Measles is a highly contagious, vaccine-preventable respiratory illness characterized by a rash of flat red spots.

Typical measles symptoms, including high fever, rash all over the body, stuffy nose and reddened eyes, usually disappear without treatment within two or three weeks, though a severe case can lead to death.

“Measles spreads like wildfire,” said the World Health Organization Regional Director for the Western Pacific, Takeshi Kasai. “It is the most contagious human disease, and it’s very good at seeking out and spreading among even small groups of people who are not immune.”

The WHO notes that Australia was one of nine countries in the Western Pacific which had eliminated measles — using a three-year period of “no prolonged local transmission” as the definition of elimination.

“In recent months, we’ve seen how swiftly and easily measles can make a comeback in communities where not enough children have been immunized,” said Kasai.

Measles cases in the Western Pacific in 2018 increased by 250%. More than two-thirds of these were in the Philippines, which has also seen 23,000 cases, with 333 deaths, so far this year. Most victims were aged under five.

Vaccination works by providing “herd immunity” — the process by which an infectious disease can be prevented from easily spreading through a community because enough people are immune to it.

“Herd immunity provides protection to those unable to be vaccinated such as infants and people with weakened immune systems,” Sheppeard said.

If herd immunity is weakened, those susceptible to contracting the virus can be at risk of infection. The disease can be imported to previously measles-free areas from countries with cases of infection.

Sheppeard said that out of this year’s 23 cases, three came from deliberately unvaccinated children but the state was “achieving 95% vaccination rates in all cohorts” — enough to create herd immunity from measles.

Spikes worldwide

In the US, 387 cases of measles have been reported since the beginning of the year, according to figures shared last month by the Centers for Disease Control and Prevention — the second highest number number of cases since measles was declared eliminated in 2000. The highest number was 667 in 2014.

Last week, in an attempt to contain an outbreak of measles that began in October, Rockland County in New York banned unvaccinated people aged under 18 from public places.

Health officials have said the proliferation of anti-vaccine rhetoric has helped fuel an increase in the number of measles and other vaccine-preventable diseases in the United States.