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Horseshoe crabs & Covid-19

A significant disagreement, on the use of an animal model in vaccine safety testing, has developed between the US and Europe.

For many years, the unique natural property in the blood of horseshoe crabs, has been essential for testing the safety of new vaccines, injectable drugs and even artificial hips, as it contains a protein that forms visible clots which identify harmful bacteria that could be dangerous if injected into a human.

Blood is “milked” in a lab from the horseshoe crab, which despite the name is not actually a crab, and they are then returned to the sea, however it’s speculated that the mortality rate is as high as 30%.

In Europe, a new synthetic alternative to horseshoe crab blood (rFC) was recognised as being safe in 2016, but in the USA, it is yet to gain approval from the Federal Drug Administration (FDA) and last month the United States Pharmacopeia announced that there was insufficient evidence to prove that the synthetic alternative was good enough.

The European advice has recently had further backing from the European Directorate for the Quality of Medicines and Healthcare and its director, Susanne Keitel, said: “When used under appropriate conditions, rFC-based methods provide the same guarantee of a product’s compliance with the test for bacterial endotoxins – and therefore, of its safety for use in patients.”

Now with the demand from US companies for sterility testing for Covid-19 vaccines, using horseshoe crabs, likely to increase there are concerns for it’s an effect on the populations of the animal and also that European vaccines tested using rFC will not be automatically approved for sale in the US.

Conservationists state that the use of crabs in the medical industry has contributed to a decline in the horseshoe crab population over the last thirty years, although biotech companies such as Charles River Laboratories, argue that thanks to good stewardship the population has in fact steadied over recent years and the Covid-19 vaccine development process would not result in the need for harvesting significantly more than usual.


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