Six people, including a baby died last week from the influenza type-A (H1N1) in different parts of the Kingdom. Most already suffered from chronic illnesses.
Two of the six flu victims died after receiving the drug oseltamivir, but doctors said the vaccine was given too late to be of help.
"Provincial governors in their areas have now been assigned to look into these cases," Public Health Minister Jurin Laksanawisit said yesterday.
He said one of these two was a one-month-old baby boy in Chon Buri, while the other was a 60-year-old man in Bangkok.
Jurin said the elderly man suffered from diabetes and emphysema at the time he came down with the flu.
There have been 34,794 confirmed infections and 218 confirmed deaths since the type-A (H1N1) flu hit Thailand last year.
The government offers free vaccines against the type-A (H1N1) flu to people in risky groups and will continue to do so till the end of this month.
Currently, 404,983 people have come forward to be vaccinated - 46 per cent have been healthcare workers and 22 people with chronic illnesses.
Some 7 per cent were people who weigh over 100 kilograms.
Jurin said the government had prepared two million doses of the vaccine.
According to a survey conducted by the Mental Health Department, 57 per cent of respondents had confidence in the vaccine's effectiveness. Those who did not said they were worried about possible side-effects.
But Jurin said few serious side-effects had been reported by those who took the vaccine.
