They note that Hanoi has been experiencing an unexpected surge in the number of measles cases, with 271 patients recorded so far this year, compared to only 60 for the whole of last year.
Last week alone, 18 measles patients were hospitalized. Most of the patients were under five and had not been fully vaccinated.
Nguyen Nhat Cam, director of Hanoi’s Preventive Medicine Center, said the disease has scattered across the city, mostly in urban districts.
No outbreak has been reported in the city so far, but many health experts have warned of the possibility of one occurring, Cam said.
He encouraged parents to take their children to medical centers across the city to get vaccinated against measles. Women wanting to get pregnant should be vaccinated earlier to ensure their kids are immunized, he said.
In 2014, a measles epidemic disease broke out in Hanoi with a record-breaking number of 1,700 cases that killed 14 people.
One death was recorded last year.
The World Health Organization (WHO) estimates that 2.6 million people who have not received measles vaccination die every year.
Measles is a highly infectious illness caused by the rubeola virus. Those infected show symptoms of high fever, dry cough, runny nose, sore throat and watery eyes.
In 2016, Vietnam became the fourth country in Asia after Japan, India and China to successfully produce a measles-rubella vaccine on its own.