SEOUL, Korea, Republic Of - South Korea administered its first available shots of coronavirus vaccines to people at long-term care facilities Friday, launching a mass immunization campaign that health authorities hope will restore some level of normalcy by the end of the year.

The rollout of vaccines come at a critical time for the country, which has seen its hard-won gains against the virus get wiped out by a winter surge and is struggling to mitigate the pandemic's economic shock that decimated service sector jobs. The vaccinations began shortly before the country reported another new 406 cases of the coronavirus, brining its caseload to 88,922, including 1,585 deaths.

“I felt very anxious over the past year, but I feel more secure now after receiving the vaccine,” said Lee Gyeong-soon, a 61-year-old nursing home worker, who spoke with reporters after receiving her shot at a public health centre in northern Seoul. Long-term care residents with mobility problems received injections from visiting health workers at their facilities.

More than 5,260 residents and workers at 213 nursing homes, mental institutions and rehab centres who are younger than 65 were to receive their first shots of the two-dose vaccine developed by AstraZeneca and Oxford University on Friday.

An unspecified number of patients and workers at 292 long-term care hospitals and in the same age group will also get the vaccine, according to officials at the Korea Disease Control and Prevention Agency.

Health authorities plan to complete injecting the first doses to some 344,000 residents and workers at long-term care settings and 55,000 frontline medical workers by the end of March.

“We have taken the historic first step toward restoring normalcy,” senior Health Ministry official Son Young-rae said during a briefing.

He said the government has decided to extend current social distancing levels for at least another two weeks, clamping down on private social gatherings of five or more people and banning indoor dining after 10 p.m., to help create a safe environment for vaccinations.

Long-term care facilities, where elders or people with serious health problems often live in crowded settings, have endured the worst of South Korea's outbreak. About 35% of the country's COVID-19 deaths at the end of 2020 were linked to these facilities, said Jaehun Jung, a professor of preventive medicine at the Gachon University College of Medicine in Incheon.

But there's criticism over the government's decision to delay the approval of the Oxford-AstraZeneca vaccines for people over 65 until the developers provide more data that suggests the shots would be effective in that age group.

Some experts, including Jung, say the decision risks the safety of people who are most vulnerable to COVID-19 when the country will be chiefly dependent on locally produced Oxford-AstraZeneca vaccines during the early part of its vaccination campaign.

Despite what the government sees as a lack of laboratory data on its efficacy in older adults, the Oxford-AstraZeneca vaccine is still showing real-world effectiveness in preventing serious illnesses and lowering death rates in the countries where it was used, the experts say. People over 80 account for just 5% of the country's coronavirus cases, but 56% of its virus-related deaths, Jung said.

Using refrigerated trucks escorted by police and military vehicles, South Korea transported 1.57 million doses of Oxford-AstraZeneca vaccines across the country from Wednesday to Thursday. These shots were among the global supplies produced in the southern city of Andong, where local pharmaceutical company SK Bioscience manufactures the vaccines under a contract with AstraZeneca.

Separately, doctors, nurses and other health professionals treating COVID-19 patients will begin receiving the shots developed by Pfizer and BioNTech from Saturday. The Pfizer-BioNTech vaccines, which South Korea obtained through the WHO-backed COVAX program, arrived at Incheon International Airport on Friday and will be transported to five major COVID-19 treatment hospitals.

South Korea plans to complete injecting the first doses to some 344,000 residents and workers at long-term care facilities, which also include mental institutions and rehab centres, and 55,000 frontline medical workers within March.

The next available vaccines are likely to go to workers at general hospitals, paramedics, quarantine workers and people over 65 years in age before broader groups of adults begin receiving shots in summer.

South Korea plans to secure enough doses to vaccinate 79 million people this year, well over its population of 51 million, through bilateral negotiations with pharmaceutical companies and COVAX, which was established to promote global access to vaccines.

While there has been disappointment the shots haven't come sooner, officials have insisted South Korea could afford a wait-and-see approach as its outbreak isn't as dire as in America or Europe.

Officials aim to vaccinate more than 70% of the population by November, which they hope would meaningfully slow the virus and reduce risks of economic and social activity.

However, experts say a safe return to life without masks would be highly unlikely this year, considering the need to monitor the vaccines' real-world effectiveness and the growing spread of virus variants that are feared to be more contagious.

“Even if we achieve the government target by November, we probably won't be able to (immediately) go back to the pre-COVID-19 days,” said Choi Won Suk, an infectious disease professor at the Korea University Ansan Hospital, west of Seoul.

“But if we maintain a certain level of social distancing and mask wearing as the vaccinations proceed, there will be a point where we would no longer be seriously worrying about a massive wave of the virus,” allowing for a certain level of social and economic activity, he said.