The Delta wave. How we got here, how we exit and how we prevent it from happening again.

The United States finds itself in yet another wave of COVID-19 infection, this time caused by a Delta viral variant that is more infectious. I have previously explained how the Delta variant has mutated to become more infectious, but that really isn’t the issue at this point. 

The real issue is how we got here, how we exit from this wave, and how we prevent it from happening again.

Why did the Delta wave happen?

The first reason we are seeing this new wave is that the virus has billions of people around the world in which it can grow and mutate. On average, only 24% of the world’s 7.8 billion people have been fully vaccinated according to world governments and health ministries. Most of us with knowledge about RNA virus mutation and vaccination expected mutants to develop, and therefor seeing a more infectious form of COVID-19 develop is not a surprise.

Current new COVID-19 cases in the United States. The highest numbers of new cases per 100,000 people (darker colors) are in states with the lowest vaccination rates. Data from Nebraska were missing.

What was not expected was the United States would be so prone to this new wave of COVID-19 infection. The reason behind the outbreak in the U.S., particularly of severe infections and hospitalizations, was clearly the low rate of vaccination, particularly in several states where rates are well below 50%. Unvaccinated individuals caused explosive outbreaks of infection in areas with low vaccination rates and led to 95% of hospitalizations.

New cases and deaths in Florida now exceed any time during the pandemic. Almost all of the deaths are in the unvaccinated.
Eran Segal

People have claimed that the vaccines are not working to protect people from the Delta variant based on the experience in countries like Israel where they are now seeing significant increases in infections. However, only 58% of Israel’s total citizenry is fully vaccinated. Experts say that’s not nearly high enough. “We have a very large fraction of our population who are paying the price for a small fraction of the population who did not get the vaccine,” said Eran Segal of the Weizmann Institute of Science. It is clear from the Israeli experience, however, that a very high percentage of citizens need to be vaccinated to prevent transmission of COVID variants.

Therefore, this highly contagious delta variant is rapidly infecting significant populations of unvaccinated, COVID-19 naive individuals. This is what led to the rapid spread of the Delta wave and provided so little time for the U.S. to manage this infection.

How do we exit this wave?

We will exit this wave one way or another, but several options provide potentially better outcomes. Much has been argued about simply allowing the infection to run rampant to develop “natural” immunity to COVID-19. There are several problems with this. First, health systems will become overwhelmed, as they are now in several southern states. Caregivers already devastated from over a year of COVID-19 care will likely become totally burned out and health care may not be available for all the infected individuals. Normal health care for other conditions will also suffer.

Importantly, so called “natural immunity” does not appear to be an improvement over vaccine immunity. A recent CDC study indicated that individuals post COVID-19 infection are 2.3 times as likely to be reinfected as those who received vaccines. This puts everyone in a more vulnerable situation going forward as these individuals will likely be targets of a future coronavirus variant.

Mass vaccination is the most rapid and safe approach to trying to end this outbreak and protect the health care system. The good news is that individuals who have waited to be vaccinated and who get vaccinated now will have almost total protection against the Delta variant and better protection over the coming months against future infection. In data from Israel in younger people, where serious cases are less common, the rate of serious cases among unvaccinated people in the under-60 crowd (3.2 per 100,000) was more than double the rate among vaccinated people. So young people also benefit from vaccination!

Individuals who are over 65 and were vaccinated six months ago or longer do have somewhat decreased immunity. However, according to Israeli Health Ministry, where the elderly population was among the earliest in the world to be vaccinated, the rate of serious Delta variant cases among unvaccinated people over age 60 (178.7 per 100,000) was nine times more than the rate among fully vaccinated people of the same age category. Half of the breakthrough cases were in people who were fully vaccinated but had immune problems. Booster vaccinations, now being done in Israel and recommended for the most vulnerable in the United States, will drive these rates even lower.

It is important to immunize everyone in contact with children younger than the age of 12 since they cannot get the vaccine, and unvaccinated infected adults could cause outbreaks during the resumption of school activities.

If we can aggressively immunize individuals, we can reduce hospitalizations and have this wave of infection die out by fall. 

How do prevent a future wave?

There is only one definitive way to prevent future COVID outbreaks like what we’re seeing with the Delta variant. That is to immunize the entire world’s population to prevent the infections that drive variant production. A recent letter from a group of public health experts is recommending just that and imploring the United States to take the lead role in this effort.

The group of more than 175 health experts proposed this to President Biden in an Aug. 10 letter sent to senior White House officials and shared with The Washington Post.

The Russians make fun of our vaccine efforts through their news and social media outlets. But it is interesting that they are vaccinated everyone including children!

“We urge you to act now,” the letter reads. “Announcing within the next 30 days an ambitious global vaccine manufacturing program is the only way to control this pandemic, protect the precious gains made to date and build vaccine infrastructure for the future.”

The group has estimated that if the letter’s proposal is adopted, 4 billion people – more than half the global population – could be fully vaccinated by the end of 2021 with U.S.-manufactured vaccines. They also argue that the more-effective RNA vaccines be used since they are better at preventing breakthrough infections rather than just serious disease.

This really makes sense since having an unvaccinated population on our southern boarder defeats many of the benefits of U.S. vaccination. Also, on Israel’s doorstep, in the Israeli-occupied West Bank and the Gaza Strip, only around 8% of Palestinians have been fully vaccinated. Israel allows only vaccinated Palestinians to get permits to enter Israel and Israeli settlements, but that is a stop gap. Infectious diseases know no boarders.

So although I know it sounds simplistic, the answer to all three of these questions is the same — effective mass COVID-19 vaccination.

Published by jbakerjrblog

Immunologist, former Army MD, former head of allergy and clinical immunology at University of Michigan, vaccine developer and opinionated guy.

4 thoughts on “The Delta wave. How we got here, how we exit and how we prevent it from happening again.

  1. I still don’t understand how an mRNA SARS-CoV-2 vaccine can confer better immunity than a natural infection. Aren’t the mRNA vaccines specifically targeting only the spike protein? Wouldn’t a natural infection cause antibodies to be produced against not only the spike protein, but also other proteins in the viral envelope, plus other viral components in general?


    1. Much like flu vaccine it suggest that the immunity to other proteins is not helping much to protect against the infection. The inactivated COVID vaccines have not been very effective. The biggest difference though is the prime-boost sequence that provides stronger initial immunity and better immune memory than a single infection.


  2. We are 75 and 80 respectively, are in good health and received our second Pfizer shoot on February 26th. Question, we are planning a trip to NYC in October and were trying to determine whether it would be important to wait the FULL 8 months before we receive our third dose or if it would be okay to have it a week or two early, so we could have move immunity when we travel?
    Thanks in advance.
    Bennet Wolper


    1. This shouldn’t make a difference as 6 months is the point where immunity seems to wane somewhat. Over 65 without medical conditions will be eligible on September 20, so I would go then and two weeks after that date (when the booster effect from the vaccine will be fully consolidated) will be October 3. This should cover most of the month!

      Liked by 1 person

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