South Korea will lengthen the period between the first and second doses of two messenger RNA COVID-19 vaccines to six weeks, due to Moderna more than halving August shipments to Korea, Minister of Health and Welfare Kwon Deok-cheol said Monday.

Kwon said in an emergency breifing that Moderna will be sending less than half of the roughly 9 million doses of the vaccine that it had promised to ship this month. 

“In a recent communication Moderna has apologized for the delays in deliveries and explained that the supply problems were affecting countries all over the world, not just Korea,” he said.

He said that ministry representatives led by Vice Health Minister Kang Do-tae will be making a US trip to speak with Moderna officials and bring forward the delivery of its vaccine in the third quarter.

Regarding setbacks with Moderna shipments in July, the ministry had said in an earlier briefing that holding the pharmaceutical company legally accountable for temporary shortfalls in deliveries was “not likely to be viable” as long as the overall target of 40 million doses is met over the year.

By Sunday’s end, roughly 10 million doses of vaccines remained in the country, according to government data: 5 million AstraZeneca doses, 4 million Pfizer doses, 326,000 Moderna doses and 100,000 Johnson & Johnson doses. Korea has placed an order for a total of 192 million doses of COVID-19 vaccines from five different pharmaceutical companies, 35 million of which have made it into the country so far.

“We remain committed to reaching the goal of giving 70 percent of all Koreans at least one dose of a vaccine by September,” the minister said. “The biggest variable remains the vaccines getting to the country on time.”

But some changes to the vaccination time frame were “unavoidable” to distribute first doses to the rest of the population as planned, the minister said. Currently, first doses are being offered to people 50 or older, with eligibility slated to open up to those younger than 50 from Aug. 26 onward.

Starting next week, both Pfizer and Moderna vaccines, two doses of which are spread three and four weeks apart, respectively, will be administered over a longer interval of six weeks, the minister said. Exceptions will be made for high school seniors and other priority groups in the education sector, who will be getting their Pfizer vaccinations within the recommended spacing of three weeks.

The minister said the vaccine delivery schedule will be “managed so that people due their second doses will be able to complete the series within six weeks’ time.”

Korea counted 1,492 more cases in the latest 24-hour period, marking the 34th straight day of more than 1,000 new cases, according to the Korea Disease Control and Prevention Agency’s situation report. The seven-day average of new cases was 1,635 as of Sunday, which is more than a threefold increase since the final stretch of the winter wave in late January.

One in 4 patients with critical COVID-19 undergoing life support were in their 40s or younger, nearly all of whom were unvaccinated. Out of 376 critical care patients, 15 percent were in their 40s, 9 percent in their 30s and 6 percent in their 20s.

Younger patients were ending up on extracorporeal membrane oxygenation, or ECMO -- the final stage of life support given to the sickest patients -- now unlike in previous waves of the pandemic, the Korean Society for Thoracic and Cardiovascular Surgery said in a statement ahead of the weekend, which attested to the severity of the pandemic here.

More than 60 percent of all COVID-19 beds for patients in severe or critical condition had been filled as of late Sunday.

Some 40 percent of the 51 million people in Korea have received at least one vaccine dose and 14 percent have been fully vaccinated since the national campaign kicked off Feb. 26.

By Kim Arin (arin@heraldcorp.com)