As expected, vaccinations have ramped up dramatically, and now we are giving more than 3 million shots a day ( https://www.bloomberg.com/graphics/covid-vaccine-tracker-global-distribution/ ). We have now given more than one-third of the population a shot. While a 70-85 percent vaccination rate has been bandied about regarding herd immunity, and this is a lofty goal, a much lower level will bring the pandemic to an effective end. Why? First, we have around one-third of the population with some natural immunity due to having had COVID. As I explained in an earlier post, "natural" herd immunity has a much lower threshold (https://salthillstatistics.com/posts/78 ), so the combination of that one-third plus vaccinations (subtracting out overlap) likely means herd immunity faster. Also, most of those at risk for serious illness have mostly been vaccinated. Close to 80% of those 65 and older have now been vaccinated with at least the first shot, meaning we are weeks away from having full protection for 80% of that group (see https://covid.cdc.gov/covid-data-tracker/#vaccinations ). Sadly, Michigan, New York, and a few other states are lagging far behind, but they will get there shortly also.
In Israel, around 90% of older people are vaccinated, but overall vaccinations plateaued at a little higher than 50%. Still, at 54% fully vaccinated (and only a couple of percent with one but not two shots), cases have fallen 97%, from more than 10,000 a day to just a few hundred (see https://www.worldometers.info/coronavirus/country/israel/ ).
We continue to see dramatic improvements due to vaccinations. While there is understandable worry that cases in the US are no longer falling, and in some places, they are rising, deaths have been declining and continue to nationwide. Below is a chart showing the change in the 7 day average number of deaths versus that of two weeks before. This has been in decline since early February and we now have about 700-800 deaths per day.
As a point of comparison, the seasonal flu causes around 400 deaths per day in the winter in a bad year and a couple hundred in a normal year. So we're not there yet but moving toward it.
What about all the variants?
The great news about the variants is that the vaccines continue to be highly effective against all major variants in the US. The South African variant, for which the vaccines have some but likely less effectiveness, was never able to get a foothold here. Instead, the British variant mostly took over, and the major vaccines appear to work very well against it. Britain had the worst of the British variant but its single-dose Pfizer vaccinations (they are delaying second doses) worked to quell their outbreak. Cases there are down more than 90% from their winter peak (like Israel, they are also at around 50% in terms of people receiving the first dose).
50% is the Number
We should certainly hope to get to 70 or 80% of the population vaccinated, or even more, and getting there will undoubtedly save lives. However, what we've seen elsewhere is that 50% vaccinations will do the trick. When will that happen? At our current rate, we need around another month. We might be able to get there faster if vaccination rates can increase a little more (we will have the supply) and some localities that lag in vaccinations could take longer, but figure that by Memorial day we will be out of this mess.