Why Are COVID Cases Dropping Off a Cliff? Where Are the Variants?
These past two weeks, there’s an undeniable trend in COVID cases which are way down. Why is this happening? Where are the variants that numerous media outlets have warned about? Let’s dig in.
The COVID Variants
I can’t keep up with the news on COVID variants or mutations. We began with the British variant and then moved into the Brazillian, and now we have hybrids like California-British. The news media keeps warning us of doom and gloom from these and saying that reopening society would not be wise. In fact, one early British prediction around the holidays was that lockdowns would definitely not be enough to stop that variant from spreading due to its high transmissibility! However, reality turned out to be quite different.
COVID Cases Are Dropping Fast
COVID daily cases worldwide (see above left) are dropping as are deaths which lag 3 weeks. In fact, we’re approaching fall 2020 levels of disease and if these trends continue, we could be at summer levels by March. Why?
That’s an interesting question. We might be tempted to say that it’s due to lockdowns, but we have huge portions of the US who haven’t gone there. For example, let’s see how California, which has extreme lockdowns compares to Florida which has schools open and near as I can tell, have handled this in a more of a Swedish “laissez-faire” approach:
Huh? Not much difference there. When I compare other areas with different strategies, I get the same results, so it’s likely not the lockdowns.
The one thing that could explain what we’re seeing is called “seasonality”. All respiratory viruses in the northern hemisphere peak in mid-January and then decline as we hit February and then the spring. This is most likely due to changes in weather and Vitamin D levels as the sun gets stronger. If that were the case, then we would expect to see the southern hemisphere in a low of cases, but their cases also peaked and then dropped just as ours did.
The single strongest explanation is immunity. While only 10-15% of the population has antibody-mediated immunity and about 15% of our US population have had their first dose of the vaccine, we don’t really know how many people have cellular immunity. This is another arm of the immune system that can kill virus without antibodies, “. Early studies suggested that many more people had cellular immunity than had antibodies. These people are called “bouncers (3-6).
Could the young bouncers have saved us all? Despite teen and college lockdowns, in my direct experience, most of the young have continued on with their lives. They just went more “underground”, so they avoid big parties that will draw attention but with school online and much less time-intensive, they’re still socializing. These are the people most likely to be bouncers. Their immune systems are strong enough that they simply don’t need to make antibodies to kill something like COVID. Hence they’re not showing up in antibody studies.
We could be at 50% or more total immunity. This is the concept that the virus is more likely than not to end up in a host which can kill it, thus reducing the frequency of transmission.
Where Are the Mutant Variants?
On December 31st, the geniuses at Imperial College London (the same ones who had predicted that the US would lose millions in the first wave) put out a warning about the very high transmissibility of a new British strain (1). That lead the BBC to report: “New coronavirus variant is “hugely” more transmissible, study finds.” The news cycle then began with some experts concluding that even lockdowns in the UK may not be enough to contain the virus. Here’s the actual caseload in the UK:
This looks just like every other country, despite the UK being in a strict lockdown. On January 15th, the CDC reported that the British variant was already in 12 states and that this could spike our cases in the next few months (about now 1+ months later). These reports continue to circulate. However, here are US cases:
Hence, it looks like while “the British invasion” worked for the Beatles, but not so far for the SARS-CoV2 virus.
Lessons from the 1918 Pandemic
Above I have graphed both the 1918 Spanish Influenza pandemic and our COVID pandemic. The hugely deadly 1918 pandemic began in 1918 in the spring of that year with military recruits. Our pandemic, according to red cross blood samples began in the fall of 2019 (7,8). In both cases, there were few deaths at the start.
In the 1918 pandemic, next comes the “second wave” which ocuured in the winter of 1918-19 and caused many deaths which corresponds to our April 2020 “first wave”. Next up in the Spanish Flu pandemic are what are called the third and fourth waves, all of which occurred in the winter/spring of 1919-20. This corresponds to our second wave winter/spring of 2020/2021.
If we true this up on a timeline, that means that we could be in the same time frame as the Spanish Flu third wave. Their fourth wave included more sporadic and localized outbreaks, but they also didn’t have a vaccine. So assuming the anti-vaccination trend doesn’t destroy our building herd immunity, we hopefully should see this virus die out sooner rather than later.
Without vaccines, why did the 1918 pandemic end? Herd immunity. They had about the same amount of social distancing and mask-wearing, but they kept schools open and limited public gatherings. There was no such thing as work from home over Zoom, so they had more people infected more quickly. Ultimately enough people were exposed so that the virus could no longer find hosts where it could survive to get transmitted.
Masks, Social Distancing, and Vaccines
As Yogi Bera once said, “It ain’t over till it’s over”. So if you’ve ever watched your favorite sports team blow a perfectly good lead at the end of a game because they let down their guard, we need to not be that team who decides it’s time to get lazy. Hence, keep washing hands, social distancing, wearing masks, and get vaccinated so that you’re part of the solution and NOT part of the problem!
The upshot? Are we at the end of this pandemic? Looking at the map of the 1918 pandemic, that would suggest that we may be. So far the variants haven’t been an issue. Will they become a bigger issue later in the spring? Only time will tell, but I would place my bets on this pandemic being over by summer, maybe fall.
(1) Imperial Collge London.New COVID-19 variant growing rapidly in England. https://www.imperial.ac.uk/news/211793/new-covid-19-variant-growing-rapidly-england/Accessed 2/18/21.
(2) CDC. Emergence of SARS-CoV-2 B.1.1.7 Lineage — United States, December 29, 2020–January 12, 2021. https://www.cdc.gov/mmwr/volumes/70/wr/mm7003e2.htm Accessed 2/18/21
(3) Dan JM, Mateus J, Kato Y, Hastie KM, Yu ED, Faliti CE, Grifoni A, Ramirez SI, Haupt S, Frazier A, Nakao C, Rayaprolu V, Rawlings SA, Peters B, Krammer F, Simon V, Saphire EO, Smith DM, Weiskopf D, Sette A, Crotty S. Immunological memory to SARS-CoV-2 assessed for up to 8 months after infection. Science. 2021 Jan 6:eabf4063. doi: 10.1126/science.abf4063. Epub ahead of print. PMID: 33408181.
(4) Iqbal H. The importance of cell-mediated immunity in COVID-19 – An opinion. Med Hypotheses. 2020;143:110152. doi:10.1016/j.mehy.2020.110152
(6) Centers for Disease Control and Prevention. Emerging Infectious Diseases. Cellular Immunity in COVID-19 Convalescents with PCR-Confirmed Infection but with Undetectable SARS-CoV-2–Specific IgG. Vol 27, Number 1-January 2021 (e-print ahead of publication)
(7) Centers for Disease Control and Prevention. Serologic testing of U.S. blood donations to identify SARS-CoV-2-reactive antibodies:
December 2019-January 2020 . https://tinyurl.com/y6mgh72z Accessed 12/3/20.
(8) The American Red Cross. Study Suggests Possible New COVID-19 Timeline in the U.S. https://www.redcross.org/about-us/news-and-events/press-release/2020/study-suggests-possible-new-covid-19-timeline-in-the-us.html Accessed 12/3/20.