A number of children in Hanoi and other northern provinces are experiencing a second measles breakout this year.
Most of the children infected have yet to receive vaccinations, said Professor Tien Dung, head of Pediatrics Ward of Bach Mai Hospital in Hanoi.
The ward is treating 30 children with serious cases. Three of the children have developed severe pneumonia.
The wet weather in the north is a favorable condition for the virus, said Nguyen Nhat Cam, director of the Preventive Medicine Center in Hanoi.
To prevent further infections, parents and teachers with infected children should quarantine them from public areas until completely healed.