The FDA plans to revise its blood donation guidelines to ensure the blood supply is protected from malaria.
The World Health Organization warns that malaria remains a substantial global health challenge, with 249 million cases and over 608,000 fatalities in 2022. Although malaria isn't considered a significant menace to the US blood supply as it is in some regions, nearly 28 million US residents voyage to regions where malaria prevails each year, and the temperature rising, scientists predict that the disease may become more of a threat in the US despite diligent mosquito control.
In the 1940s, the US Centers for Disease Control and Prevention reported about 65,000 cases of malaria annually. However, during World War II, the US government targeted mosquitoes to avoid having trainees contract the illness in malaria-infested areas in the south, which proved to be a useful endeavor. By 1949, the CDC declared malaria no longer a significant health issue in the US, and the WHO announced the country free of malaria in 1970. Today, the US logs roughly 2,000 cases per year, though most are travel-related.
Despite the low risk of domestically acquired malaria, the CDC identified a few cases in Texas, Florida, Maryland, and Arkansas last summer, the nation's first local malaria cases since 2003. Due to these findings, the Food and Drug Administration (FDA) authorized a test designed to detect evidence of malaria in donor blood in March this year. Manufactured by Roche, the Cobas malaria test can detect RNA and DNA from the malaria-causing parasite in donor blood, organs, and tissue.
Although malaria transmission through blood transfusion is not prevalent, an infection may cause severe symptoms or mortality, as per findings from one study published between 1963 and 1999, with 93 cases stemming from contaminated blood in the US and ten resulting in death. Another study between 2000 and 2021 revealed 13 malaria cases related to blood donations, with seven of these incidents involving donors adhering to current FDA eligibility criteria.
Despite the guidelines' complexity, Jennifer Scharpf, the associate director for policy in the FDA's Office of Blood Research and Review, remarked that they do not prevent all cases. The current procedures involve donor history questionnaires, precluding donors with malaria or prior travel to malaria-endemic areas in the previous three months. The regulations are distinct for platelet and plasma component collection.
However, these questionnaires present limitations and are "error-prone," according to the FDA. Furthermore, the three-year deferral period may not be sufficient to identify asymptomatic donors unaware of their malaria status, particularly those from malaria-endemic nations with developed immunity.
The deferral of potentially healthy donors based on travel history alone can be anywhere between 1% and 3% of all donors, with blood banks facing difficulties in garnering sufficient donors. Scharpf updated the advisory committee that approximately 50,000 to 160,000 donors are turned away due to travel history, and studies indicate that many of them don't return once they are eligible.
The FDA is exploring two possible options to revise the guidelines: (1) selective testing of donors based on malaria infection, recent travel to malaria-endemic areas, or prior residency, (2) testing all donations at least once and then selectively testing donations from donors at risk of exposure. The first option gained majority consensus, while the second seemed more excessive to most advisory committee members.
The FDA is currently contemplating imposing regulations to test blood in areas exhibiting locally transmitted cases. However, several committee members questioned the necessity of this measure. Dr. Sanjay Ahuja, director of the Rainbow Hemostasis & Thrombosis Center at the Rainbow Babies & Children's Hospital in Cleveland, observed that making a decision on when to test all donated blood in such areas proves challenging.
With malaria transmission via mosquitoes remaining rare and treatable, the FDA faces the challenging task of navigating guidelines to enhance blood safety while maintaining potential donor pool size.
In a meeting, Ahuja expressed his thoughts, "This has a lot of intricacies, in my opinion. I'm not sure if we should say 'yes' to this without having more evidence of local transmission."
During the open forum for audience opinions, leaders of certain blood-related associations advocated for a careful approach towards altering the guidelines.
Ralph Vassallo, the incoming chair of the Transfusion Transmitted Disease Committee for Association for the Advancement of Blood & Biotherapies, supports the prospect of the new malaria test's potential for enhancing blood safety. It might also increase the number of donors by eliminating unwanted restrictions, especially for individuals with uncommon blood types from Latin American, Asian, and African countries.
However, he pointed out that there are no clinical trials that verify if the test lowers the chance of malaria transmission through transfusion.
Vassallo emphasized the need for adaptable testing methods and expressed that while his group, together with America's Blood Centers and the American Red Cross, backs testing all donations in areas with malaria transmission, a solitary case shouldn't prompt such measures.
“The FDA should advocate for modeling studies crafted in collaboration with malariologists using top-notch estimations about parasite quantities during asymptomatic infection prior to issuing final directives,” he suggested.
The committee didn't make a decision on these strategies, but the FDA acknowledged the discussion and plans to use it as they contemplate adjusting their guidance.
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The FDA is considering implementing selective testing for malaria in donor blood based on their travel history or residency in malaria-endemic areas, as highlighted in the discussion. Despite the complexity of the current guidelines, Jenny Scharpf noted that they do not prevent all cases of malaria in donated blood.
Source: edition.cnn.com
