FDA plans to update its blood donation guidelines to protect the nation’s supply from malaria

CNN
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The U.S. Food and Drug Administration is considering requiring blood banks to use a new test that can detect malaria parasites in the blood of certain donors, and it is seeking advice from its independent advisers on the best way to achieve its goal of zero cases linked to transfusions without unnecessarily prohibiting certain people from donating blood.

The World Health Organization says malaria is a significant global health problem, with 249 million cases and more than 608,000 deaths in 2022 alone.

Malaria is not considered a major threat to the United States’ blood supply as it is in other countries. But nearly 28 million U.S. residents travel each year to areas of the world where malaria is common, according to the FDA, and as more Americans travel and the planet warms, scientists have predicted the disease could become more likely in the United States, even with aggressive mosquito control.

In the 1940s, the U.S. Centers for Disease Control and Prevention said in a presentation to the FDA advisory committee Thursday that the United States had about 65,000 cases of malaria a year — but that changed when the country needed healthy military personnel to fight around the world. Second war. Knowing that many would train in malaria-prone areas of the South, President Franklin Delano Roosevelt’s administration waged a war against mosquitoes that bore fruit.

By 1949, according to the CDC, malaria was no longer considered a significant health problem in the United States, and the WHO declared the United States free of the disease in 1970.

The United States still has about 2,000 cases a year, according to the CDC, but most are travel-related.

The CDC noted that although the risk of locally acquired malaria in the United States continues to be “extremely low,” as recently as last summer it warned doctors to monitor for locally acquired cases. There were a handful of non-travel cases in Texas, Florida, Maryland and Arkansas last year, the first locally acquired cases of malaria in the United States since 2003.

In March, the FDA approved the first test to screen donors blood for evidence of malaria. The Cobas malaria test, made by Roche, can detect RNA and DNA of the malaria parasite in donor blood, organs and tissues.

Transmission of malaria through blood transfusion is not common, but infection can trigger serious symptoms or even death, studies show. A CDC study found that between 1963 and 1999, there were only 93 cases transmitted through blood donation in the United States, but 10 of them died.

Another study found 13 cases of malaria linked to blood donations between 2000 and 2021, the FDA said, but seven of the cases involved donors who met current FDA eligibility criteria.

“It’s complicated and it doesn’t prevent all cases,” Jennifer Scharpf, associate director for policy in the agency’s Office of Blood Research and Review, said of the current guidelines.

The FDA told the committee Wednesday that its current guidelines are very “complex” and that blood bank employees must evaluate several potential risk factors.

Blood banks use a donor history questionnaire to screen people who have had malaria or lived in a country where the disease is endemic in the past three years. People also cannot donate if they have traveled to a country where malaria is endemic in the previous three months; or if they resided in a country where malaria is endemic, if they have have spent less than three consecutive years in a country where malaria is endemic, or if they have ever traveled to a malaria endemic area in the previous three years. The rules are slightly different for collecting platelets and plasma components.

These questionnaires have limitations and the screening process is “error-prone,” the FDA said. Exclusion periods may also not be sufficient to detect asymptomatic donors, particularly for residents of countries where malaria is common, as they may have partial immunity from previous infection.

On the other hand, current guidelines disqualify a large group of healthy potential donors, the FDA said. Some estimates say that between 1% and 3% of all donors are turned away based on their travel history alone, and blood banks say they can never get enough donors.

Scharpf told the committee that about 50,000 to 160,000 donors may be deferred each year, and studies show that many deferred people often do not return, even when they are eligible to donate.

The FDA is considering several strategies to update its guidance.

The first consideration is to selectively test a donor’s blood based on their history of malaria infection, whether they have traveled to a malaria endemic area in the previous three months, or whether they has previously lived in a country where malaria is endemic. Another option is to test all donors at least once and then selectively test donations from people at risk of exposure, including those who have already had malaria and those who have traveled to a malaria-endemic area in during the previous three months.

Most members of the advisory committee seemed to favor the first option, believing that the second seemed far-fetched.

“The incidence of the disease is so low and it is treatable,” said committee member Dr. Richard Scanlan, professor, vice chair of the Laboratory Medical Transfusion Service and medical director of Oregon Health & Science University .

The FDA is also considering requiring testing of all blood donations in areas where there has been a recent case of locally transmitted malaria, but committee members seemed less sure of this idea.

Committee member Dr. Sanjay Ahuja, director of the Rainbow Hemostasis & Thrombosis Center at Rainbow Babies & Children’s Hospital in Cleveland, said that if there is proven local transmission, the decision on when to test all blood donors of the region is “difficult”. .”

“There are so many nuances to this,” Ahuja said. “I think it might be a little too much in my opinion, but I don’t know if more evidence of local transmission should be put in place before we say ‘yes’ to that.”

During the meeting’s public comment period, leaders of some blood supply organizations encouraged the FDA to take a cautious approach to changing the guidance.

Ralph Vassallo, new chairman of the Association for the Advancement of Blood and Biotherapeutics’ transfusion-borne diseases committee, said his group joins America’s blood centers and the American Red Cross in believing that the new malaria screening test shows real promise for improving blood safety and could improve donor availability by removing unnecessary “donor exclusions,” particularly among subsets of donors with uncommon blood types, such as those of Latin American, Asian and African countries.

But, he told the committee, no clinical studies show the test reduces the risk of transfusion-transmitted malaria.

Vassallo also encouraged the FDA to use flexible testing strategies and said that although the groups support limited testing of all donations in ZIP codes with local malaria transmission, a single case should not be enough to trigger such tests.

“The FDA should support formal modeling studies designed in consultation with malariologists using the best available assumptions about parasite levels during asymptomatic infection before issuing final guidance,” he said.

The committee did not vote on the proposed strategies, but the FDA said it would take the discussion into consideration when considering changes to its guidance.