The virus slows down. Is it the vaccine?

We look at various countries and try to see how the vaccination rate affects the number of cases and the death rate.

First of all, there is a remarkable drop in worldwide infections and deaths. While some rich countries have received enough vaccine doses to make a difference, I don't think there was enough vaccine to justify this global effect.

Just to be clear, I have never said that the vaccine does not work. So far, all hard evidence available to me points to the fact that the vaccine does what it should: it protects people from becoming infected and, if vaccinated people become infected, the infection is less severe. Thus, the vaccine does work.

There is debate if the immunity from the vaccine is better or worse than the immunity acquired from infection. I will not get in that debate, but we should acknowledge, from past experience, that some vaccines give immunity that is worse and some better than from infection itself. Regardless, any immunity is good and will reduce infections and deaths.

About one year ago, in February 2020, I have placed the Coronavirus mortality at 0.2% of the infected population. This is vastly less than the number of people tested positive because most people with mild symptoms won't be tested.

A pandemic stops when most people have been immunized through either infection or vaccination.

In the following, we will take countries one by one, starting from the ones who have vaccinated the most and see if and why the slowdown is due to the vaccine.

Israel

Israel is the world leader in vaccination, with about 90 does given for 100 people. That is somewhere between 45% and 90% vaccinated, depending on the fraction of people who received one of 2 doses. The Israeli policy has been to offer people 2 doses as fast as possible. Thus, the number is close to 50%.

Infection rates are relatively low in Israel, with 618 deaths per million. That is, based on my expected 0.2% mortality, only about 30% of Israelis have been infected.

Given that infection and vaccination are poorly correlated, it's reasonable to assume that 50% of the 70% uninfected people are vaccinated.

This leaves us with 35% of the population susceptible.

Due to this relatively large susceptible population, the reduction in both infections and deaths is nowhere near as spectacular as the vaccine progress.

Sure, once almost the entire population is vaccinated, which will happen in the near future in Israel, the Coronavirus will become a rare disease.

United Arab Emirates

The UAE ranks 2nd in the world after Israel, with 60 doses of vaccine for 100 people.

Shockingly, there is only a modest drop in cases, and deaths are almost at their maximum. If we believe that the worldwide drop in cases and deaths has something to do with the vaccine, then the UAE must be giving it to their camels.

That is a very poor performance for the word'd second most successful nation in the vaccination campaign. The reduction in both deaths and cases is well below the world average in UAE.

The reason is that, despite the 30% of people who are immunized by vaccine, the virus has infected rather few in the UAE. At 119 deaths per million, and a 0.2% mortality rate, this is only 6%.

With 6% infected and 30% vaccinated, most of the population remains susceptible, which explains the lack of reduction in both deaths and cases, despite the UAE being the second in the world in the race to vaccinate.

To see the positive side, in the UAE, most vaccinated people have not been infected, so they're getting a good return on investment for their vaccine. A vaccine given in UAE is far more likely to save a life, compared to one given in NY.

United Kingdom

With nearly 30 vaccines given per 100 people, the UK comes a distant 3rd in the vaccination race. The Brits used half as many vaccines per capita as the UAE and a third of what was used in Israel.

Yet, the number of cases and deaths has plummeted -- a result Israel and UAE can only dream of.

How come, given that so much fewer doses of vaccine were given?

The UK had a controversial policy of giving only one dose of vaccine. This would mean as much as 30% of Brits have received one dose, so the fraction of vaccinated people may be comparable to the UAE. Yet, that's not enough.

The answer, in my view, lies in the immunity from the virus.

The death rate in the UK is nearly 1800 people per million. At 0.2% mortality, that means 90% of the population has been infected. Some of them would have been infected in the first wave and their immunity may be waning now.

With 90% infected and 30% vaccinated, this leaves only 7% who have not been exposed to the virus in the form of either infection or vaccine.

Despite being everywhere, the virus now finds it hard to find a virgin victim to infect. Hence, the epidemy dies down, mainly due to nature taking its course and not because the UK is the worlds' 3rd most prolific immunizer.

United States

With about 20 vaccine doses per 100 people, and with many Americans getting 2 shots, the impact of the vaccine in the US is relatively small.

Yet, the drop in cases and deaths is quite large -- not as big as in the UK, but larger than Israel and UAE.

The American mortality from Covid-19 appears to be above my universal perdition of 0.2%. This may be due to obesity and the healthcare system -- good healthcare for some, allowing people to live close to deaths for a long time making them susceptible to Covid-19 , and lack of coverage for others, making them more likely to die from an acute infection.

The US has lost 0.16% of the population, so taking a one-size-fits all approach to mortality and assuming the 0.2% holds, 80% of the Americans have been infected. Add to that something between 10-20% vaccinated (depending if one or 2 does are given) and we are left with 16-18% susceptible.

It's probably a bit more due to the higher mortality in America and to the fact that some people infected in first wave have lost their immunity.

If the infection immunity is perfect, the vaccine only adds 2-4% to the immune population. Not too much, and not a justification for the much bigger reduction in cases and deaths than we've seen in Israel and UAE, despite them using 4.5 and 3 times more vaccines per capita.

In the United States, the drop in cases in Hawaii is comparable to NJ and NY, which makes no sense, given that factor of 8 difference in infection rate.

NY and NY should have herd immunity from first wave and new infection should be mostly people catching it for the second time. Thus, milder.

Europe

Across Europe, a similar picture emerges. Serbia, with nearly as many doses per capita as the US doesn't seem to do better than other countries like Belgium, France, Spain or Italy.

It seems countries see cases and deaths grow until somewhere close to 0.2% mortality and then they stop.

Success in containing the first wave doesn't imply success in containing the 2nd. Herd immunity seems to play the crucial role in stopping the epidemic.

When the epidemic stops due to lockdowns or summer, the virus comes back and often comes near the 0.2% mortality. Going beyond 0.2 appears difficult, which is consistent to a large fraction of the population being infected.

Sure, immunity doesn't last forever. Thus, we will probably see subsequent waves and new genetic variants infecting people for a 2nd or 3rd time, generating additional mortality.

Sources:

Mortality and cases come from
https://www.worldometers.info/coronavirus/

Vaccination status comes from
https://ourworldindata.org/covid-vaccinations https://ig.ft.com/coronavirus-vaccine-tracker/?areas=gbr&areas=isr&areas=usa&areas=eue&cumulative=1&populationAdjusted=1