"We know from our discussions with the family, and from what they did that the baby was quite sick on the Saturday and the Sunday when they travelled, and certainly on the Monday when they got back.''
It was taken to an urgent medical centre twice on Monday, and was also treated at the Waitakere Hospital emergency department, he said.
All family members had since been tested for measles, and members of the household suspected of being at risk of contracting the disease were in isolation, he said.
Waitemata District Health Board this afternoon confirmed the baby had been discharged in a stable condition.
Dr Hoskins said it was possible several other passengers on the Singapore Airlines flight could come down with the disease.
"We think there were about 250 people on the flight, but we're actually working through that information now.
"It would be very unusual on a plane with over 200 people with a disease that's as infectious as measles for everybody else on the plane to be immune either from having had two vaccines or from having had measles themselves.''
According to the New Zealand immunisation schedule, the first vaccination injection for measles, mumps and rubella is given at 15 months old. The second one is given at age 4.
Singapore Airlines marketing manager Murray Wild said dealing with cases of communicable diseases in travellers was not uncommon for airlines.
"What we do is assist with the health service to identify the passengers seated in proximity or close proximity to the infected passengers.''
None of the cabin crew working on the flight had fallen ill because it was a requirement for them to be vaccinated, he said.
Thirteen other cases of measles have been confirmed in the North Island following an outbreak linked to an individual who attended a Sydney dance festival last year.
