The United States has been working furiously on developing a number of therapeutic options to treat COVID-19. In addition we have several vaccines in phase III trials under the Trump administration’s Operation Warp Speed. The U.S. is certainly not alone, Mexico and Central America have been hit hard by the coronavirus as well. Scientists, and veterinarians experienced in producing snake antivenoms in Costa Rica have been laboring to produce a therapeutic formulation of equine antibodies against the COVID-19 virus. In theory these preformed antibodies would work in much the same manner as convalescent plasma from recovered COVID-19 patients. The lead Costa Rican biochemist is Roman Macaya who also runs the nation’s public health clinics and hospitals. Much of the research is taking place at the University of Costa Rica’s Clodomiro Picado Institute (named for a Costa Rican scientist). The Clodomiro Picado Institute has extensive experience developing snake antivenom extracted from horse antibodies. The Institute has carried out this type of work for some fifty years and their antivenom products are shipped to countries around the world. The Institute houses more than 100 horses that are used as live factories to manufacture antibodies to various toxins. The horses are gradually inoculated with small doses of snake venom to which they form strong immunity to the toxins in the venom over time. The horse plasma is withdrawn and purified to produce snake antivenom. Similar antidotes have been produced for scorpion and spider venom and to counteract the neurotoxins of rabies, botulism and diptheria. These equine formulations have proven safe in humans and have rarely produced any adverse reactions. Six horses were donated to the Institute by locals to study COVID-19 antibody harvesting. Three horses were administered a portion of the surface spike protein while the other three horses received the spike protein plus three additional viral proteins. After receiving four inoculations every two weeks, the horses produced an adequate level of antibodies. The horses’ plasma was then withdrawn and purified, separating the desired antibodies. The plant produced a total of 1,000 vials (10 ml each) of purified equine antibodies. Five vials contained antibodies against the spike protein alone and the other five had antibodies against the four different proteins. According to the the scientists each vial holds 80 times the antibodies as 800 ml of convalescent human plasma.
The equine antibodies were tested at George Mason University’s National Center for Biodefense and Infectious Diseases. Various dilutions of the antibodies, when exposed to cell cultures of the virus, effectively neutalized the virus. Studies of the equine antibodies on COVID-19 patients will begin this month in a group of 26 hospitalized patients who do not require admission to the ICU. The results of this trial are expected by the end of September and if positive a larger trial will be undertaken. Positive results will likely result in an upscale production and the addition of more horses at the Clodomiro Picado Institute. The Institute received a $500,000 grant on Aug. 13 from the Central American Bank for Economic Integration permitting it to continue its important work. The equine antibodies are not as “high tech” as monoclonal antibodies but they are easier to produce and less expensive. The hope is Costa Rica can not only meet the medical needs of the region but be capable of helping other countries with an even greater need such as Brazil.