A strategic monkey reserve for developing vaccines?

We aren’t monkeying around, this is for real. Vaccine developers in the US are facing a peculiar problem: there aren’t many monkeys available for conducting pre-clinical trials (the step before human trials). “We can’t find any rhesus any longer. They’ve completely disappeared,” Mark Lewis, the CEO of Bioqual, a contract research organisation that specialises in animal testing, tells The Atlantic.


Why monkeys?

• Tests on monkeys typically represent the last step before human clinical trials. The immune system of monkeys and humans are very similar, hence the use case. Rhesus macaques and cynomolgus macaques are commonly used. Monkeys only get mildly sick from Covid-19, yet they provide distinct advantages.
• Pharma companies, typically, are wary of testing vaccines on children, even in clinical trials. Primate testing could address this gap.
• Another advantage: You could conduct challenge trials. Challenge trials verify the true efficacy of a vaccine by deliberately infecting the test subject. It is a step that some are advocating in clinical trials (on humans). But deliberately infecting humans when there is no known cure to Covid-19 has been a non-starter. Scientists who work with primates thus say challenge trials on monkeys can be a solution.

Why the shortage?

• China provides nearly 60% monkeys imported to the US. Since the pandemic, they have stopped all exports, reserving them for trials in various vaccines that China is developing.

And the reserve?

• Hence, vaccine developers and scientists working on primate testing are calling for a strategic monkey reserve in the US, not just for Covid but for the “next pandemic” as well.

Note: Some promising Covid vaccines candidates have advanced well beyond this stage. But health experts have said we may need more than one vaccine to completely get rid of the coronavirus. According to the Milken Vaccine Tracker, 207 vaccines are being studied, many of them in the pre-clinical stage. And these “slow vaccines” matter.