I first talked about Horseshoe Crabs a while back. You can find it in this article. The blood of horseshoe crabs is extracted and used in vaccines. Horseshoe crabs live in the sea, where there is a lot of bacteria. The Horseshoe crab has NO immune system and no way to fight off infection. However, they have a chemical that so far as we know is totally unique to them. This chemical called Coagulogen binds to and inactivates unwanted bacteria, viruses and fungi. It forms a gooey barrier around the bad stuff.

So we extract the blood from the Horseshoe crabs to use in vaccines, if no gooey barrier forms in the vial, we know the vaccine is untainted and there is no bacteria, or active virus or fungus inside.

We know blood is very important in scripture. One instance that automatically comes to mind is the plagues setting the stage for the escape from Egpyt, Exodus 12:7,12-13 NAS:

Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel of the houses in which they eat it. For I will go through the land of Egypt on that night, and fatally strike all the firstborn in the land of Egypt, from the human firstborn to animals; and against all the gods of Egypt I will execute judgments—I am the Lord. The blood shall be a sign for you on the houses where you live; and when I see the blood I will pass over you, and no plague will come upon you to destroy you when I strike the land of Egypt.

We see in Leviticus 17:11 NAS

For the life of the flesh is in the blood, and I have given it to you on the altar to make atonement for your souls; for it is the blood by reason of the life that makes atonement.’

Blood was needed under the law to cover the sins of the people and make things right between them and God again; to show the people the seriousness of sin and that the cost of sin was high to bring reconciliation to God. We find in Hebrews 9:22 NAS

And almost all things are cleansed with blood, according to the Law, and without the shedding of blood there is no forgiveness.

Right now we have a very serious problem in the world with the Coronavirus. The best path forward seems to be herd immunity to break up the quick transmission of this deadly plague. The problem is, with so much vaccine needed, the amount of Horseshoe crabs being harvested is not sustainable. 30% of Horseshoe crabs die after having blood extracted, and the rest are much slower and don’t breed and spawn like normal horseshoe crabs. The numbers of horseshoe crabs have been decreasing since 1990 and with so many more now being harvested to handle vaccine needs for the coronavirus, it is worried they might end up on the endangered list, and we will lose the ability to use their blood to cover our needs in the future.

If all Christians still needed animal sacrifices to make us right with God, would we have caused shortages in the animals of today? Would animal rights groups have even allowed it? Thankfully God loved us enough to provide us a new way. Hebrews 13:11-12 NAS tells us

For the bodies of those animals whose blood is brought into the Holy Place by the high priest as an offering for sin are burned outside the camp. Therefore Jesus also suffered outside the gate, that He might sanctify the people through His own blood.

1 Peter 1:18,19 also tells us:

...knowing that you were not redeemed with perishable things like silver or gold from your futile way of life inherited from your forefathers, but with precious blood, as of a lamb unblemished and spotless, the blood of Christ.