Millions in Russia, Ukraine Hit by Severe Flu Strain : Health: Officials in Kiev say more than 9 million will be struck by month’s end. Virus reportedly doesn’t match U.S. variety.

A large, hard-hitting influenza epidemic is sweeping across Russia and Ukraine, according to U.S. and Russian health officials.

More than a million people may have taken ill in the region over the last two weeks, with 500,000 stricken during the second week of December in Moscow alone, the officials said.

“It is a very severe influenza, producing high temperature,” said Dr. Yuri Ghendon, a virologist with the Research Institute for Viral Preparations in Moscow. “It is not clear if it is a unique strain. We are still researching it. There are other outbreaks in all parts of Russia. It’s like a fire--you cannot believe it is so fast.”

Officials in Kiev, Ukraine’s capital, have reported even more striking outbursts of influenza to the World Health Organization and the U.S. Centers for Disease Control and Prevention’s Flu Branch in Atlanta. There, at least 1.25 million people, half of them schoolchildren, have fallen ill, and officials in the Ukrainian Health Ministry predict more than 9 million nationwide will have been struck by month’s end, according to information received by Dr. Nancy Cox, head of the Flu Branch.

Three months ago, the CDC sent flu surveillance kits, containing laboratory reagents necessary to identify flu strains, to authorities in both Russia and Ukraine. Both countries now say their flu doesn’t match the three strains that are circulating in Asia and the Americas. Those three strains, the most common of which is Johannesburg-A, are the basis for the flu vaccine currently available in the United States.

Scientists classify flu strains according to proteins on the viral surfaces that stimulate human immune responses. The Johannesburg-A strain is in a class dubbed H3N2. And so is the Moscow strain, Ghendon said. Health authorities in nearby Finland have also reported the arrival of a H3N2 flu strain, closely resembling the Johannesburg-A. But Ghendon said he doubted the new Russian flu was close enough to the Johannesburg strain to be preventable by this year’s vaccine.

Cox said Americans will probably be adequately protected by the currently available Johannesburg-A vaccine. But she said she can’t be sure until her lab receives samples of the Moscow and Kiev viruses.

“What we generally see is related [flu] strains circulating worldwide at any given time. How closely they’re related may vary from year to year, of course, but we think all of this year’s flus will be [closely related] H3N2s,” Cox said. “It’s very unusual--it only occurs in a pandemic situation--that there’s something totally different, and I really don’t think that’s the case this year.”

During this century, the world has been hit by five flu pandemics, in 1918, 1946, 1957, 1968 and 1977.