Updated July 29.
Enhancing mosquito control. Encouraging safe sex. Advising people to minimize travel to infected areas.
As public health officials hustle to implement strategies like these to undermine the threat of the Zika virus, one such tactic could exacerbate a different health concern: maintaining the nation’s supply of donated blood.
The Food and Drug Administration is encouraging blood banks — which already often struggle to meet demand — to turn away potential donors who might be at risk. Specifically, people who have traveled to a country where the disease is being spread, or had sex with someone else who did, should not donate for four weeks. The protocol is being followed by clinics across the country.
Meanwhile, in two Florida counties where experts worry the virus is being locally spread, blood banks have been advised to temporarily halt blood collection. The FDA is recommending neighboring counties do the same, unless they have systems in place to test blood for Zika.
“We need to protect the blood supply,” said Lawrence Gostin, a professor at Georgetown University and faculty director of its O’Neill Institute for National and Global Health Law. “It would be a major scandal if there were cases of Zika transmitted — particularly if it affected women of childbearing age.”
To date, there are more than 1,600 confirmed cases of the virus reported in the continental United States, almost all of which were connected to travelling abroad. And on Friday, Florida state officials announced four cases of Zika in the state were likely caused by local mosquitos.
Though evidence is limited, there’s a possibility Zika, which can cause birth defects when contracted by pregnant women and is primarily transmitted by mosquito bites, could also be spread through blood transfusions. That connection, while drawing less attention than links to sex or childbirth, is raising the stakes for what could happen if the virus spreads unchecked in the United States.
And therein lies the issue.
Even in locations where Zika isn’t likely to pose as great a threat, blood banks are worried that the impact of the FDA’s advisory — because of the sheer number of people traveling to areas where the virus is active and growing case count — could undercut their supplies.
Experts say the advisory makes sense. There is no widely available, government-approved blood test to screen donations, though one is being used on an experimental basis for blood collected in Puerto Rico and Houston.
“With blood supply, you can’t even tolerate a low risk,” Gostin said. “You would undermine confidence in the blood supply system in the United States, and that’s something we’ve sought to avoid at any and all cost.”
Even though the risk of infection is small, caution is still warranted, Gostin and others assert. Especially for people with serious injuries, blood transfusions can be key to recovery. Unsafe blood has spread a number of dangerous viruses, such as HIV. And the consequences of getting Zika — especially for women in the early stages of pregnancy — can be severe, including birth defects for children or miscarriage.
But that caution can still have consequences. Many banks report they are already feeling the squeeze.
“We’ve absolutely seen a reduction,” said Jayne Giroux, director of community development at SunCoast Blood Bank in Florida.
The limitation matters, especially since blood banks typically face difficulties in maintaining adequate reserves, Giroux said. And not just in Florida. “It’s a concern everywhere.”
The American Red Cross, which is responsible for about 40 percent of the health system’s donated blood, estimates that, so far, only one-tenth of one percent of its donors were turned away because of Zika exposure. But, a spokeswoman noted, that doesn’t account for people who otherwise would have donated but never came. United Blood Services, which operates banks in 17 states, estimates its donations are down by 3 percent this year — there are several potential causes, and Zika is likely among them, said Barbara Kain, a spokeswoman.
But even if some facilities experience only a mild supply pinch, the downturn could compound other difficulties. Summer is already a tough time for blood banks to collect with people travelling more and colleges — robust collection sites — on break.
The donor drop-off is probably greater in Southern states, where people more frequently travel to affected areas like Mexico, parts of the Caribbean and South America, said Louis Katz, chief medical officer of America’s Blood Centers, another national blood bank network. Though Zika has had an impact, he emphasized that it’s only one among many challenges blood banks are grappling with. Banks are trying to stock up in anticipation of any shortages, Giroux said. Blood plasma can be collected and frozen for years, but other components have shorter shelf lives.
There’s another option: Federal officials hope to expand the blood testing technology that’s being used for Puerto Rico and Texas, so banks can collect blood from donors, screen it and then discard whatever comes up positive for Zika. The FDA has given two tests the go-ahead to be used in clinical trials, which means blood centers can become testing sites and use the technology. One test was developed by Roche. The other, which gained that conditional FDA approval in June, is manufactured by Hologic. If the Zika threat grows, more blood banks will try to get in on using those, said Steven Kleinman, chief medical advisor at the American Association of Blood Banks.
There is “tremendous interest” from blood banks and testing sites to use new screenings, said Tony Hardiman, Roche’s vice president for blood screening. But it could take until the end of summer before most Southern states have easy access to testing.
Federal officials are also pushing ahead on blood technology.
The Department of Health and Human Services has awarded about $50 million in grants to two companies that are trying to improve “pathogen reduction technology,” which takes infected blood and removes the virus, making it safe for use. That would mitigate some blood shortage concerns around transfusions, noted Gary Disbrow, acting director of the division of chemical, biological, radiological and nuclear countermeasures at HHS’ Biomedical Advanced Research and Development Authority.
Such technology already exists for treating viruses such as Zika in platelets and plasma. Researchers are working to improve it and develop a similar “cleanser” for red blood cells, the most commonly transfused part of blood. But, experts noted, that could take years.
The uncertainty, meanwhile, comes in a field where planning is already difficult, Giroux said, and where not having enough supplies on hand can have major consequences.
“You never know, from day to day, what the needs are going to be. You can’t predict a ruptured aorta. You can’t predict a motor vehicle accident,” she said. “Any time a virus or anything new pops up that we don’t yet have a screening test for, people should be concerned.”