African swine fever (ASF) outbreaks in China pose an unexpected threat to the global supply of heparin due to its impact on pig populations. Since August 2018, China has culled more than one million pigs in efforts to contain the spread of ASF within the country. Widespread culling of pigs consequently affects the supply of raw materials needed to produce heparin, which is derived from mucosal tissues in pig intestines. Heparin is a critical anticoagulant drug used to treat and prevent the formation of blood clots in blood vessels in healthcare. As pig herds continue to become infected and culled, should the United States form contingency plans in the event of a heparin shortage?
ASF was first reported in Kenya in the 1920s, and now in the last decade has spread considerably across Asia. ASF is a highly contagious and fatal viral disease that exclusively affects domestic and wild pigs, with a mortality rate as high as 100%. Ongoing outbreaks in China pose the greatest threat to the global supply of heparin due to the country being the largest pig supplier in the world. China supplies 80% of the world’s raw materials needed to produce heparin, and also roughly 60% of the United States crude heparin supply. In July 2019, the leaders from Congress raised concern to the United States Food and Drug Administration (FDA) regarding a heparin supply shortage due to the prolonged epidemic.
Although there is no evidence to suggest a supply concern according to the FDA, heparin is currently listed as a drug in shortage. While there are several other anticoagulants available that are comparable to heparin, no suitable replacements have been identified due to its immediate effects when administered to a patient in the healthcare setting, among other chemical and molecular advantages. Heparin is the only practical anticoagulant drug used in the United States for interventional use in open heart surgery and dialysis. The main alternative previously used in the United States was bovine-sourced heparin. This alternative was discontinued in the 1990s due to pig-sourced heparin being more potent and the concern for prion transmission. Sheep-sourced heparin is another alternative, yet it is not available for clinical use in humans.
In the event of a supply shortage, it is likely that healthcare systems will become stressed due to the limitations of heparin alternatives. For the United States, the FDA needs to formulate a contingency plan since it does not have the flexibility like other countries to employ the use of bovine-sourced heparin. Although the FDA encourages the reintroduction of bovine-sourced heparin, the agency does not endorse its use in the clinical setting. Diversifying the global supply across species is fundamental to reduce the risk of a global shortage. Since August 2018, nearly five million pigs have been culled throughout Asia due to ASF outbreaks. As the outbreak shows no signs of slowing down, the United States should prepare for this as a potential health emergency.
Frankie Catalfumo is an epidemiologist with experiencing leading emergency preparedness and response operations in support of the federal government and international agencies relating to emerging infectious diseases and natural disasters. During his career, he has supported the Centers for Disease Control and Prevention, the Department of Defense, and the Pan American Health Organization to strengthen and enhance global health security.