Vietnam is facing a stiff challenge to rein in its deadliest COVID-19 outbreak in a task made harder by the nation's low vaccination rate.

But vaccine supplies from China are filling an urgent need as authorities step up their efforts to get more doses from diverse sources into the country.

On Thursday, residents of Binh Duong, a southern province neighboring Ho Chi Minh City, lined up to receive their first COVID-19 jabs. The province, like the country's business hub, is one of Vietnam's virus hot spots as the Delta variant of the coronavirus cuts a swath across the country's south.

The province began a vaccination campaign on Thursday, using 1 million doses from Chinese drugmaker Sinopharm. The supplies were sent by Ho Chi Minh City, Vietnamese national radio broadcaster The Voice of Vietnam reported.

The crisis fueled by the Delta variant has reinforced the need for the country to step up mass inoculations, said experts in pointing to the way lockdowns have hurt the economy and people's livelihoods.

Despite the government's efforts, as of Sept 1, only 17.81 percent of Vietnam's population had received at least one jab, and only 2.8 percent of people were fully vaccinated against COVID-19, figures from Oxford University's Our World in Data project showed. This puts Vietnam among the countries with the lowest vaccination rates in Asia.

"The calculus now is to protect the healthcare system and to try to reduce the number of people coming into hospital and dying," said Guy Thwaites, director of the Oxford University Clinical Research Unit in Ho Chi Minh City.

Vietnam was earlier hailed for keeping the pandemic under control, with the country reporting low infection numbers and fatalities for more than a year until April. But the latest wave, which involved a large outbreak in Ho Chi Minh City, Vietnam's biggest city, has changed the whole story.

Infections increased from fewer than 3,000 in late April to 550,996 by Tuesday, according to reference website Worldometers. The number of deaths rose from 35 to 13,701 during the period. Around 80 percent of fatalities have been recorded in Ho Chi Minh City.

China was the first country that provided Vietnam with COVID-19 vaccines in large quantities.

In Binh Duong, the 1 million doses set aside came from a purchase of 5 million shots of the Sinopharm vaccine by Saigon Pharmaceutical, which has been licensed by the Vietnamese health ministry to import jabs to speed up the inoculation campaign.

With the spike in infections driven by Delta, Vietnam is rushing to get vaccines to protect a nation of 97 million people.

Vietnamese Prime Minister Pham Minh Chinh has urged the World Health Organization to send more vaccines.

Maurizio Trevisan, dean of health sciences at VinUniversity in Hanoi, said the government is aggressively pursuing vaccine purchases in the market and seeking donations.

Roger Lord, senior lecturer of medical sciences at the Australian Catholic University, said low rates of vaccination will mean a greater number of people will become infected, become severely ill and require hospitalization.