The number of hand, foot and mouth disease (HFMD) cases in Vietnam is 10.2 times higher over the first five months of 2012 than it was for the same period last year.
According to the Ministry of Health's report on Friday, 46,277 HFMD cases have been recorded across Vietnam since the beginning of this year.
Twenty-seven deaths have also been reported, 1.7 times more than last year, it said.
The ministry noted that cases with serious complications concerning heart and brain function, as well as the respiratory system have been reported at major hospitals including the Hanoi-based National Hospital of Pediatrics and the Ho Chi Minh City-based Children Hospital I.
It is also taking the disease less time to become serious and turn deadly.
It said a patient who did not display the symptoms associated with HFMD, such as blisters and fevers, ended up having HFMD when her condition worsened and tests were conducted, according to the ministry.
Dr. Nguyen Tran Hien, chief of the National Institute of Hygiene and Epidemiology, said his agency is cooperating with the National University of Singapore to study the Enterovirus 71 (EV-71), which causes most HFMD cases in Vietnam, to see if it is mutating.
The institute will also ask the ministry for permission to cooperate with China in conducting human trials of the EV-71 vaccination produced by that country, Hien said.