The survey began on Tuesday at hospitals, deputy director of the city Department of Health, Nguyen Van Vinh Chau, said.
Of the remaining 14 percent, 90 percent are children under 18, and were found mostly at industrial parks and quarantine zones around the city, he said.
A survey in October at the HCMC Hospital for Tropical Diseases of 349 patients found 55 percent with severe symptoms, he said, adding only 40 percent of vaccinated people had severe symptoms in contrast to 74 percent in the unvaccinated group.
Only 12 percent of fully vaccinated people had severe symptoms, he said.
He said though the surveys were minor and do not reflect the overall coronavirus situation, they more or less confirm a conclusion reached by global health experts: fully vaccinated individuals have greater protection against Covid-19 and significantly lower chances of getting severe symptoms.
"You can still get infected even after vaccination, and death is possible without early intervention. But that chance is much lower for those who are vaccinated. So fully vaccinated individuals still need to follow coronavirus prevention measures."
Data from the HCMC Center for Disease Control for the past two weeks suggests that new cases and hospitalization rates are rising in the southern metropolis, according to Chau. The increased number of hospitalized cases could be due to multiple factors, including fewer quarantine zones, he said.
He warned that outbreaks could return if people are careless. Even with high vaccination rates, the influx of people returning for work in the city might be another variable to watch out for, especially if they are unvaccinated, he said.
Considering its infection rates in the past two weeks, the city should be designated as at ‘high risk’ of coronavirus, but he said its high vaccination rate and treatment capabilities managed to put it at ‘medium risk’.
Pham Duc Hai, deputy head of the HCMC Steering Committee for Covid-19 Prevention and Control, said the rising numbers of infections, hospital admissions and deaths is a sign that the situation is still evolving in HCMC.
He said many people have become too complacent and ignore coronavirus prevention measures like social distancing and wearing masks.
HCMC recorded 981 new cases on Thursday, bringing the total number in the latest wave since April to 435,717.