Antibodies and the Race to Cure Coronavirus
The coronavirus continues to spread across the world like a wildfire, leaving more than 137,000 (a number that continues to rise by the hour) dead in its wake. Researchers are racing to put an end to this nightmare. Studies on antibodies could be the quickest path to the finish line. But it may not work for everyone.
Passive Antibody Therapy
Passive antibody therapy has been around since the 1890s. It was a common treatment for serious diseases up until the 1940s when antibiotics took off. The practice involves filtering antibodies from the blood of people who have successfully recovered from a given illness and using them to help people who are sick with that virus to recover. Previous research has shown people develop measurable antibody responses to other coronaviruses. This means doctors may be able to take blood donations from COVID-19 survivors and turn them into potentially life-saving treatments for the most vulnerable.
According to a study recently published in The Lancet, doctors used plasma from recovered patients to help others recover during the first deadly SARS outbreak. Doctors turned to the treatment as a last resort for patients who weren’t responding to other therapies. Similar approaches have helped patients survive Ebola, MERS and H1N1.
Promising Immune Studies
A preliminary report released by the Department of Radiology at Beijing Anzhen Hospital and Capital Medical University offers promising findings. The researchers infected four adult rhesus macaques with COVID-19; all four fell ill. One was sacrificed on the seventh day for necropsy, which revealed evidence of the virus replicating in the nose, pharynx, spinal cord, heart, bladder and skeletal muscle tissues.
Two of the surviving monkeys were reinfected 28 days in, with the third left as a control. The infected monkeys experienced short temperature spikes but otherwise appeared well. All swab tests came back negative for COVID-19. Researchers sacrificed one of the reinfected monkeys for necropsy 5 days later, but there was no evidence of viral replication anywhere in the animal’s body. This means the possibility of catching the disease twice may be low — and also that passive antibody therapy might effectively treat COVID-19.
Potential Pitfalls
For as many promising results as have been reported on the recovery front, others haven’t shown hopeful outcomes. A study just published by Nature shows some people may be prone to COVID-19 reinfection, and others might even be relapsing. Genetics could play a role in susceptibility. But even if these people only represent a subset of the population, that one hurdle could pose some serious issues.
A study on COVID-19 disease severity looked into possible connections between previous infections with similar coronaviruses and an issue called antibody-dependent enhancement (ADE). For reasons not yet understood, some people who have developed immunity against other coronaviruses may experience a life-threatening inflammatory response when exposed to the coronavirus that causes COVID-19. If coronavirus immunity does sometimes provoke ADE, then any therapy focused on boosting an immune response against it could contribute to more severe illness in some people.
These findings support an article released in February by Taiwan News that people becoming reinfected with the virus were more likely to suffer deadly complications. If a subset of people are prone to reinfection, then immune-based preventative measures will be useless for these individuals. Even worse, passive antibody therapy could work as an ADE, causing more harm than good in people prone to severe infection. More research is desperately needed to determine whether alternate avenues need to be explored.
There’s still so much we don’t know about COVID-19, but researchers are working hard to find solid solutions until a vaccine becomes available. We’ll keep you informed as the advances come in.
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