Based on the cost of vaccines and the cost of delivery, it would take around $200 billion to vaccinate every person on earth, which is about 6% of the wealth currently controlled by 400 Americans. After paying for this vaccination program, these individuals would still be $40 billion richer than they were before the pandemic.

Even setting aside the desperate humanitarian need for a global vaccination, there is still a strong self-interested argument that wealthy countries should do it: the longer covid circulates in the world, the more chance of a vaccine resistant variant emerging, and undoing all the vaccine progress we've already made.

The World Health Organization is currently organizing a global vaccine donation program which aims to vaccinate about 20% of residents in poor countries by the end of 2021, and even that approach has substantial funding shortfalls.

Malaria is one of the worst infectious diseases ever visited on mankind, possibly killing more people than any other infectious disease in history. In the 20th century alone, malaria killed more people than the Black Death.

All of these deaths are preventable. Treating and preventing malaria is a well understood science, universally practiced in the developed world.

It is estimated that malaria could be globally eradicated by 2030 for a cost around $1.84 per at-risk person per year, or around $100 billion total. This would be around 3% of the wealth currently possessed by the 400 richest Americans.

Around 800 children will die of malaria today.

Americans have about $81 billion in medical debt that is sufficiently past due as to appear on their credit report. These are generally small debts, with a median value of $207 dollars per person.

These debts hinder the credit of over 50 million Americans, and do long term damage to their housing, employment, and borrowing options.

Every single person in America could be lifted above the poverty line with a one-time cash subsidy of around $10,000 per impoverished family (and about $7,000 for impoverished individuals). The total cost would be $170 billion, a little over 5% of the wealth currently controlled by 400 individuals.

Around 844 million people have no access to clean water of any kind. About the same number have no access to a toilet or latrine of any kind, and therefore defecate in the open.

Contaminated water is a major source of disease, including cholera, dysentery, and typhoid. It is estimated that contaminated water kills about 829,000 people every year, making it one of the world's biggest killers. The cost to provide clean water and waste disposal for everyone on earth would be about $240 billion, or 7.5% of the wealth controlled by the 400 richest Americans.

Paid maternity and paternity leave are estimated to cost around $12 billion per year. This is 0.39% of the wealth controlled by 400 Americans. It is 5% of the wealth they accrued in 2020 alone.

If they repeated this payment every year for the next 100 years, it would equal 39% of the wealth they control today.

40% of the wealth is equvilent to $1,280,000,000,000