Will we return to normal in 2021?

Last update: Wednesday 1/6/21

There's one thing about which Republicans and Democrats are in unanimous agreement ==> 2020 was a nightmare, so 2021 will bring a welcome return to normal living, right? Well, maybe. It all depends on the answers to a few questions, some of which are not known at this time.

Public health experts have told us many times in 2020 that social mitigation slows the spread of COVID-19; but herd immunity will bring the pandemic to its end. So let's start with a brief review of herd immunity. Here's what Wikipedia has to say:

"Herd immunity ... a form of indirect protection from infectious disease that occurs when a sufficient percentage of a population has become immune to an infection, whether through vaccination or previous infections, thereby reducing the likelihood of infection for individuals who lack immunity. Immune individuals are unlikely to contribute to disease transmission, disrupting chains of infection, which stops or slows the spread of disease. The greater the proportion of immune individuals in a community, the smaller the probability that non-immune individuals will come into contact with an infectious individual."

In other words, when a large enough percentage of the U.S. population has been vaccinated, an infected person will be far more likely to come into contact with people who have been vaccinated than with people who have not been vaccinated during the week to 10 days during which the infected person is contagious. Therefore the small percentage of the population who have not been vaccinated are unlikely to become infected because they are unlikely to come into contact with anyone who is contagious. Now for the questions:

1. What percentage of the population must be vaccinated in order to achieve herd immunity?
Many epidemiologists have suggested that 60 to 70 percent may be sufficient, but Dr. Fauci has recently estimated that the required percentage may be closer to 90 percent for COVID-19 

• ''How Much Herd Immunity Is Enough?", Donald G. McNeil Jr., NY Times, 12/24/20
  

2. How many vaccinations per day will be required for the U.S. to achieve herd immunity by the end of 2021? 
The U.S. 2020 population was approximately 330 million. Applying Dr. Fauci's 90 percent estimate for herd immunity would require 297 vaccinations.

According to the CDC, as of the end of 2020 less than 3 million people had been vaccinated, so we still need to vaccinate around 294 million people. The average monthly rate should be approximately 294/12 = 24.5 million vaccinations per month ... or 24,500,000/365 = 67,000 per day.

The estimate for each state will be based on 90 percent of each state's population. For example, Maryland's 2020 population was about 6 million. So the average number of vaccinations per month in 2021 would be approximately (6,000,000 * .90)/12 = 450,000 ... or 450,000/365 = 1,200 per day

These rough estimates should be kept in mind when reading CDC or other reports that note the number of vaccinations that have actually occurred. If the reported number of actual vaccinations falls well below these estimates more often than they stay above them, we will be unlikely to achieve herd immunity by the end of 2021 for the nation as a whole or for a particular state.


3. Will enough people in the U.S. agree to be vaccinated to achieve herd immunity by the end of 2021?

According to the December 2020 issue of the KFF Vaccine Monitor, their most recent survey found that only 71 percent of the respondents said that they "definitely" or "probably" would get a vaccine for COVID-19 if it was safe and free. This percentage is higher than the 63 percent share that KFF found in a September 2020 survey, but it is well below the 90 percent share that Dr. Fauci estimates will be required to achieve herd immunity. Although the share will probably increase as the vaccine rollout gains momentum in 2021, there is no guarantee that it will reach 90 percent in time to achieve herd immunity by the end of the year.

KFF's December survey also explored what they call "vaccine hesitancy", i.e., those who said that they probably or definitely would not get vaccinated even if it was safe and free. Note that Dr. Fauci's 90 percent estimate implies that a population won't achieve herd immunity if more than 10 percent of the public are vaccine hesitant. Here's what the KFF survey found out about the vaccine hesitancy of the overall public and various subgroups of the public:

"About a quarter (27%) of the public remains vaccine hesitant, saying they probably or definitely would not get a COVID-19 vaccine even if it were available for free and deemed safe by scientists. Vaccine hesitancy is highest among Republicans (42%), those ages 30-49 (36%), and rural residents (35%). Importantly, 35% of Black adults (a group that has borne a disproportionate burden of the pandemic) say they definitely or probably would not get vaccinated, as do one third of those who say they have been deemed essential workers (33%) and three in ten (29%) of those who work in a health care delivery setting ."

4. Will vaccinations produce asymptomatic super spreaders?

According to the following article in the New York Times, "The new vaccines will probably prevent you from getting sick with Covid. No one knows yet whether they will keep you from spreading the virus to others — but that information is coming."

• "Here’s Why Vaccinated People Still Need to Wear a Mask",  Apoorva Mandavilli, NY Times, 12/9/20

Hopefully, we will soon learn that vaccines do, indeed, prevent us from spreading the virus to others ... otherwise, our return to normal living will become more complicated than most of us had anticipated.

• Complication #1 -- If vaccination prevents illness but does not prevent people  from becoming infected and contagious, herd immunity will never be achieved, no matter how large the percentage of the population becomes vaccinated. The virus will keep on circulating. But no one else will get severely ill, hospitalized, or die after everyone becomes vaccinated.
  
  
• Complication #2 -- Vaccinated people who become infected and contagious will be asymptomatic, so social distancing and masks will continue to be required. In other words, we cannot go back to normal living until everyone has been vaccinated.
  
  
• Complication #3 -- How could we stop infected/contagious people from becoming super spreaders? How could we stop them from resuming their normal way of living -- no social distancing, no masks, etc -- before everyone becomes vaccinated?

5. What will we do if mutations arise that require new vaccinations? 

Finally we come to the troublesome possibilities. Throughout 2020, experts cautioned us that the virus gives rise to mutations from time to time, i.e.,  it commits "errors" when making copies of itself. A new copy might not be an exact replica of the original. Most of the changes are insignificant in that the erroneous copy behaves more or less the same way as the original when it infects a human. These irrelevant changes have enabled epidemiologists and other experts to track the spread of COVID-19 around the world and within a country. Infection tests identify the location of the first victim of a new mutation; then the locations of subsequent victims of the mutation are tracked.

A few weeks ago a significant mutation was first identified in the United Kingdom. The mutation was significant because it seems to spread about 70 percent faster than the previous versions. Indeed, it has quickly spread to many other countries, including the U.S.

• United Kingdom, "Boris Johnson Tightens U.K. Lockdown, Citing Fast-Spreading Version of Virus", Mark Landler and Stephen Castle, NY Times, 12/19/20
  
  
• "Discovery of Virus Variant in Colorado and California Alarms Scientists", Apoorva Mandavilli, NY Times, 12/30/20
  
  
• "How Does the Coronavirus Variant Spread? Here’s What Scientists Know", Apoorva Mandavilli, NY Times, 12/31/20
  

It spreads faster, but its effects don't seem to be more lethal, i.e., it does not make its victims sicker or make them more likely to die. The good news is that the experts think that the vaccines that are currently being distributed will also block the spread of the new mutation. Meanwhile, nations are responding to the mutation by imposing stricter social mitigation guidelines on their populations. 

Another mutation has been detected in South Africa, and like the British variant this one spreads faster but does not seem to make people sicker or make them more likely to die.

• South Africa, "Covid-19 Vaccines Expected to Work on South Africa Coronavirus Strain", Gabriele Steinhauser, Wall Street Journal, 1/4/21

A more sinister mutation might be more lethal than the current varieties, i.e., make victims sicker and more likely to die. But if a sinister mutation could be blocked by current vaccines, nations could invoke the same responses-- current vaccines plus stricter social mitigation.

A "Groundhog Day" nightmare would be a significant mutation that was not blocked by current vaccines. If such a mutation appeared, we would be zapped back to early 2020 before vaccines that blocked the original COVID-19 virus were developed. As in early 2020, our only defense would be adherence to carefully managed social mitigation guidelines. Hopefully, like Bill Murray in the movie, we will do a better job at controlling the spread of the virus next time ... and the time after that ... and the time after that ... and the time after that... :-)