Some experts are saying we need “herd immunity” to beat coronavirus.

But how do they know and why do they insist we need a *vaccine to get it?

The answer is a true story that involves a woman milking a cow, an Egyptian mummy, and General George Washington.

If it was one thing the country's first president worried about even more than the British, it was the disease they brought with ‘em.

Smallpox killed way more of Washington’s men than the war itself and it was new to America. In fact less than one in four of Washington’s men had immunity. The disease spread like wildfire through the rest.

However that didn’t happen to the redcoats because they had herd immunity.

Even if one soldier was vulnerable, he was surrounded by immune comrades so less likely to be exposed. That’s because more of the British had already survived the pox and because of a new technique catching on in England: A doctor would take smallpox from a sick person and stick it in someone else's arm.

The technique is called “inoculation.” It would give people smallpox, but most people had milder cases.

Today, the world would not take such a risk, as not everyone survived the procedure. 

But in 1777, George Washington had no safer option and less than a year into the war he did something no one had ever tried: He inoculated every soldier in his army in secret.

Historians think it may have decided the war.

Soon after losing America, England did beat smallpox.

Dr. Edward Jenner solved a mystery from out in farm country.

Milkmaids who caught cowpox from cows, also gained protection from smallpox.

This was great news because cowpox was much less dangerous to people.

The cowpox virus became our first vaccine.

Signs of smallpox in ancient Egyptian mummies tell us it took at least 3,000 years to finally find a safe way to beat it.

Now in  the coronavirus era, we’re a lot better at vaccines.

After a half a year without one for COVID  only 2 or 3% of people on Earth have natural immunity.

A vaccine is the only way we know to get to the 60 or 70% we need to start benefiting from herd immunity without risking millions of lives.

Cows probably won’t give us that vaccine. but they’ll still get the credit.