Herd immunity has always been hard to define with COVID-19. Is it at 70%, 60%, or even less? How many people have already been infected when so many infected people show no symptoms. Some efforts to test people randomly have shown antibodies in 1/3 of the people tested. An NIH study estimated that the number of undiagnosed cases maybe as many as 5 times the number of diagnosed cases. This would mean that the number of people who have had the virus is triple or quintuple the number of confirmed cases or over 100 million to 150 Americans may have had the virus and have some immunity. Add to that number an increasing number of people vaccinated daily and herd immunity might be here sooner than we thought. The rapid decline in hospitalization and deaths is happening across the board of states--ones that have more restrictions and ones that have fewer restrictions. Social distancing may have less to do with the reductions than herd immunity. Our horrible holiday spike may have just pushed us closer to finally getting closer to herd immunity. We should remember that it was only herd immunity that ended the 1918 pandemic. While the amazing technology has created new vaccines at a record pace we may find that the 2019 pandemic was ended in the same way as in 1918 with some boost from the vaccines.
On the vaccine front, the good news keeps coming. We see many news stories about the effectiveness of each vaccine to prevent infection with the COVID-19 virus. While we debate how we should change our behavior even after being vaccinated, we might be missing the most crucial story. The vaccines prevent deaths from the virus at 100% and hospitalizations at 99.5%. We have lived with coronaviruses all of our lives and the chances are that we have all had one of these viruses in the past. One of the colds we have experienced could very well have been a coronavirus. After a few days, we resumed normal activities without disruptions to our lives. Here is how the NY Times story spelled this reality out:
"........all five of the vaccines — from Pfizer, Moderna, AstraZeneca, Novavax and Johnson & Johnson — look extremely good. Of the roughly 75,000 people who have received one of the five in a research trial, not a single person has died from Covid, and only a few people appear to have been hospitalized. None have remained hospitalized 28 days after receiving a shot. To put that in perspective, it helps to think about what Covid has done so far to a representative group of 75,000 American adults: It has killed roughly 150 of them and sent several hundred more to the hospital. The vaccines reduce those numbers to zero and nearly zero, based on the research trials."
While the variants of the virus are concerning to the spread of the virus the vaccines while not as effective as they are with the original virus still seem to be very effective in preventing death and hospitalizations.
It seems that the immunity of the RNA vaccines is 92% two weeks after the first shot. England has already decided to delay the second shot of the Astra Zenica vaccine for up to 12 weeks to prioritize getting more people the first shot. The US is still sticking to the 3 to 4-week interval for now but given the supply shortage, it is worth investigating delaying the second shot as a way to get more people with some vaccine.
Pfizer has asked that the FDA approve the storage of their vaccine for 2 weeks at temperatures that are available in normal freezers and not the super cold freezers at -70 degrees. This will allow their usage at most hospitals and pharmacies that have only had the capacity to use the Moderna vaccine.