March 1, 2022 -- War in Ukraine could reverse the plunge in COVID cases in the region with a combination of low vaccination rates and residents pushed together in hiding or packing on transports to leave the country.

Those who do get severely infected in cities under siege could face hospitals already packed with people with war injuries and lack of supplies, some warn.

“That’s a toxic mix of COVID patients with battle injuries,” Eric Toner, MD, senior scholar at the Johns Hopkins Center for Health Security in Baltimore, Maryland, told Medscape Medical News.

He added that transporting liquid and bottled oxygen is “problematic and dangerous in a war zone.”

According to Reuters, the World Health Organization said on Sunday that Ukraine is running out of oxygen.

"The oxygen supply situation is nearing a very dangerous point in Ukraine. Trucks are unable to transport oxygen supplies from plants to hospitals across the country, including the capital Kyiv," WHO Director-General Tedros Adhanom Ghebreyesus and WHO Regional Director for Europe Hans Kluge said in a statement.

Before the Russian invasion last week, Toner said, COVID cases in Ukraine had dropped about 30% from their Omicron peak but were still high at 62 cases per 100,000. For comparison, the United States is currently at 20 cases daily per 100,000, according to the New York Timestracker.

In the crisis, he said, tracking the spread will be difficult.

“I would have to think there’s going to be an uptick in COVID cases, but no one will know how big or how bad because there will be no data,” he said.

He noted that news photographs and videos show unmasked crowds huddled in subway stations, basements and packing on transports to countries including Hungary, Poland, Romania and Slovakia.

Additionally, he said, “Ukraine had a low rate of vaccination – about 35% or so -- before the war started and I’m sure no one’s doing vaccinations now.”

He said surrounding countries need to prepare for an uptick in those needing medical care for COVID.

Fortunately, he said, many of the surrounding countries have high vaccination rates but they presumably are going to be seeing many refugees who aren’t vaccinated. Also fortunate is that surrounding countries have already had their Omicron surges and coupled with high vaccination rates will have high levels of immunity.

He said managing COVID numbers is likely to drop in priority.

“People will not be focusing on the pandemic in Ukraine for quite a while,” Toner said.

Ron Waldman, MD, MPH. professor emeritus of global health at George Washington University in Washington, DC, told Medscape Medical News that cause for alarm regarding COVID spread may be premature.

Waldman, who currently lives in Portugal, said though COVID is surging in some parts of the world, the number of cases in in Europe, as in the United States, are plunging rapidly.

“The incidence of COVID seems to be declining everywhere regardless of vaccination status,” he said.

He acknowledged that with higher population density infected people may come in contact more easily with people who are not infected and high mobility is also considered to be an increased risk factor for COVID spread.

However, he said, “Refugees are frequently viewed with fear and with suspicion and are frequently tagged with labels they don’t deserve. We’re going to be looking t a lot of people – I think the numbers are about a half million now --who are fleeing an armed conflict out of fear for their lives and the lives of their families. And to tag them with a label of ‘COVID spreaders’ does not have any business in the equation.”

He said given the positive epidemiological trend of decreasing cases and milder infection from the Omicron variant, “I don’t think we can allow fear of COVID from refugees to interfere with our humanity.”