HIV in America: New York City Was First 'Hub'

Also, the surprising true story of 'Patient Zero'

  • by Michael Smith
    North American Correspondent, MedPage Today
    October 26, 2016

The virus that eventually brought HIV/AIDS to light probably arrived in the U.S. in 1970 or 1971, immigrating from Africa though Haiti, researchers said.

And the center of the early American epidemic was New York City,
according to Michael Worobey, DPhil, of the University of Arizona in Tucson, and colleagues.

The findings come from a genetic analysis of HIV-positive blood samples stored in 1978 and 1979, long before the virus and its immune-damaging effects were discovered, Worobey and colleagues are reporting online in Nature.

"The samples contain a large amount of genetic diversity," Worobey told reporters in a telephone briefing -- so much that they can't represent an outbreak whose origins were close to the time the blood samples were taken in the late 1970s.

Instead, Worobey said, the genetic diversity is "direct evidence of many years of circulation for this virus in the U.S. before HIV and AIDS were finally recognized."

He and colleagues put the first introduction of the virus -- subtype B of group M of HIV-1 -- in the early 1970s.

But how it got to the U.S. remains "an open question," Worobey said. It could have been carried by a person "of any nationality," he said, or perhaps transferred in contaminated blood products.

The B subtype itself can be traced to Kinshasa, the capital of what is now the Democratic Republic of the Congo, from where it was brought to the Caribbean in the mid- to late-1960s, he said.

The researchers also analyzed the virus that infected the man long known as "Patient Zero" -- a Canadian flight attendant called Gaetan Dugas -- and showed it must have arisen later in the U.S. epidemic than the first cases in New York.

In other words, he could not have been the person who brought the virus to the U.S., according to Richard McKay, PhD, of the University of Cambridge in England.

"He was simply one of thousands of people infected before HIV was recognized," McKay told reporters.

McKay noted that the identification of the man as the index patient of the U.S. epidemic began as a misunderstanding -- he was part of a cohort of men under study by the CDC and was dubbed Patient O, because he came from "O"utside California. Later the capital letter was mistakenly read as a zero.

But Dugas did not begin travelling as an Air Canada flight attendant until 1974, McKay said, so the current data showing the HIV epidemic came to New York from the Caribbean in 1970 or 1971 is additional evidence that he was not the index patient.
Worobey told reporters the current work has been several years in the making and required the development of a new technique to sequence old and degraded HIV RNA. The researchers used blood samples stored as part of studies in the late 1970s of hepatitis B among men who have sex with men in New York City and San Francisco.

The New York analysis by Worobey and colleagues was based on a subset of volunteers who had been part of a study of more than 8,000 homosexual men conducted in 1978 and 1979, while the San Francisco analysis used data on more than 6,000 men studied at about the same time.

Worobey said there might be similar sets of stored samples elsewhere in the U.S. but they haven't come to light.

From five of the New York samples and three of those from San Francisco, they reported, they were able to derive complete viral genomes. Those from New York, Worobey said, are more genetically diverse than those from San Francisco, suggesting a later introduction into the West Coast city.

As well, the prevalence of HIV among the participants in the studies was 6.6% in New York and 3.7% in San Francisco, again suggesting that New York was the "hub" of the burgeoning epidemic, he said.

"HIV had spread to a large number of people many years before AIDS was noticed," Worobey said.

While the number is complete genomes is small, he said the researchers are confident that they give a true picture of what happened.