Ho Chi Minh City found 64,300 people to have contracted the novel coronavirus after rapid-testing over 1.6 million samples in high-risk areas in the past week; a 3.8 percent positive rate.
Luong Truong Son, former deputy head of the HCMC Malaria Parasites Institute, said such a ratio was "normal and there's no need to be frightened."
Until now, the city's strategy was to proactively track down cases by quarantining everyone having come into direct contact with previously confirmed patients in centralized camps and locking down entire neighborhoods with cases.
With this approach, cases found in areas under lockdown and quarantine normally accounted for 80-95 percent of the total daily tally.
However, because the quarantining and locking down strategy is no longer being applied, a majority of cases are being detected in the community now, Son said.
Epidemiologist Truong Huu Khanh, a consultant with the infectious and neurological diseases department at the city's Children's Hospital No.1, said it was "inevitable" that most of the new cases are local transmissions because the sources of infections were already spread "deeply" in the community.
"More cases found means more infections are separated from the community."
"This is a good sign because it would help the healthcare sector have a clear picture of the outbreak and come up with suitable solutions," he said.
Experts say that HCMC is on the right track in speeding up its mass test campaign because it is now the only way to assess at what level the outbreak is at now.
Besides, if more cases are missed in the community, the number of new cases will multiply many times in just a few days, they add.
The municipal Steering Committee for Covid-19 Prevention and Control said last Sunday that while most samples in high-risk areas had been collected by Friday, testing needed to be speeded up in low-risk areas.
The city administration has requested local authorities to ramp up sample collection, specifying that in low-risk areas, the first round of testing be done before August 30 and the second before September 6. High-risk areas have been told to finish their second round of testing before September 1.
Son said that the positive rate on the number of tests in the past days was similar day after day, proving that the source of infection was already existing and spreading continuously everywhere in the city.
It also meant that the health sector "has not been able to control the outbreak."
"Only when the number of infected people decreases steadily and 100 percent of new infections are detected in the community can the anti-pandemic strategy said to be successful and in line with the principle of safely coexisting with Covid-19 like seasonal flu.
"That could be done in a week or two, depending on the community allowed to stabilize and come to terms with this idea," he said.
Nguyen Huu Hung, deputy director of the municipal Health Department, said the positive rate of 3.8 percent in high-risk community was "acceptable" as it was lower than the 5 percent benchmarked by the World Health Organization.
"HCMC is a densely populated city which acts as the trade center of the country. Without mass vaccination, the Covid-19 community outbreak could return anytime after restrictions are lifted," he said.
The epicenter of Vietnam's fourth Covid-19 wave, which broke out four months ago, HCMC has recorded 215,810 cases to date. Of these more than 104,800 have recovered and more than 8,700 have died.
Home to 13 million including migrants, the city has vaccinated 287,991 with two doses and over 5.57 million with one dose.
"Medicine package for Covid-19 patients" campaign aims to support patients self-isolating at home. Each donation worth VND380,000 ($16.65) can help buy medicine for one patient. For more information regarding donation methods, kindly refer to this link.