And now for some encouraging news from Catherine Saint Louis of The New York Times.
“By the end of this week, all blood banks in the continental United States must begin testing donated blood for contamination with the Zika virus. Many banks are doing so already, and the early results indicate that the country has dodged a bullet — for now.
“Screenings in a dozen states suggest that Zika infection remains exceedingly rare. Among the approximately 800,000 blood donations tested in the past six months or so, about 40 were initially positive for the virus.
“’It is good news that we are avoiding the transmission of Zika,’ said Dr. Susan Rossmann, the chief medical officer at Gulf Coast Regional Blood Center in Houston.
“Still, she noted, it may not be surprising there are so few possibly positive cases, because blood banks have been dissuading people from donating if they recently traveled to an area in which the virus is circulating.
“The screening effort is regulated as two gigantic clinical trials in which every blood donor is enrolled as a participant. All the results, therefore, are reported to the companies.
“By Friday, Roche’s machines had screened 475,000 donations in the United States, excluding Puerto Rico. Just 25 have been “initially reactive” for Zika infection, said Tony Hardiman, who leads the company’s blood screening program.
“’Compared to Puerto Rico, it’s tiny,’ he said.
“Roughly 1 percent of the blood donors in Puerto Rico were infected by July, with 1.8 percent of them testing initially positive in the last week of surveillance, according to the Centers for Disease Control and Prevention.
By mid-October, roughly 348,000 donations had been screened using the test made by Hologic Inc. and Grifols. Fourteen were initially positive for the Zika virus.
“It may be that not all of these samples are truly contaminated. The technology is still in development, and the manufacturers are scrambling to confirm their results with further investigations of the donors.
“Of three donors examined by Hologic and Grifols, all seem to have been infected outside the United States. One donor gave blood at United Blood Services in Reno, Nev., after visiting Nicaragua. Another, a New Yorker, had been to Trinidad. The third lives in Arizona and had visited Mexico.
“All three donors had minute traces of the Zika virus in their blood, detected between 41 and 97 days after travel abroad, Jeffrey Linnen, an associate vice president at Hologic, told attendees at a recent conference for AABB, the standards-setting group for most blood banks nationwide.
“Viral material detected after 40 days is unlikely to be live virus, said Dr. David O. Freedman, an infectious disease specialist at the University of Alabama at Birmingham.
“’The farther along you are after infection, the more likely you are just detecting residual breakdown products from dead virus pieces that are still circulating,’ he said.
“In August, the Food and Drug Administration required all blood banks to screen each of the millions of blood donations collected annually for Zika. Eleven states in high-risk areas had to put in the new safeguards in a month. The rest must do so by Friday.
“At the time, experts feared that Zika-infected mosquitoes would begin turning up in states along the Gulf Coast, prompting outbreaks like those seen in South America and threatening the nation’s supply of donated blood.
“Universal screening was necessary to avoid transmission of the Zika virus in donated blood, particularly to pregnant women. If exposed to the virus in utero, fetuses can have brain damage, visual and joint problems, and muscle tone so rigid it restricts movement.
“Florida is the only state with documented local transmission of the virus. In July, the F.D.A. temporarily halted collection of blood donations in Miami-Dade and Broward Counties until screening for the Zika virus could be put in place.”
Source: The New York Times