SARS-CoV-2 Update for March 27th
The fourth wave in the United States is here, why it should be different that previous waves, the numerous forces at play, and vaccinations continue to scale.
The Counterpoint is a newsletter that uses both analytic and holistic thinking to examine the wider world. My goal is that you find it ‘worth reading’ rather than it necessarily ‘being right.’ Expect regular updates on the SARS-CoV-2 pandemic as well as essays on a variety of topics. I appreciate any and all sharing or subscriptions.
The fourth wave within the United States has begun. Given the springtime re-opening impulse across the Northern Hemisphere and the difference between linear vaccination increases but exponential viral spread, it is not entirely unexpected. Various factors will make this wave unlike the previous ones and while yet another wave is by no means good, there remain reasons to be optimistic, especially if we continue to take non-pharmaceutical interventions (masks, physical distancing, etc.) seriously.
There have been 30,160,868 confirmed cases of COVID-19 in the United States. The seven-day average of daily cases is 61,422. Adjusting for Mississippi’s backlog reporting on March 12th, the seven-day average had stayed between 50-55k for nearly three straight weeks. The past three days have seen a clear breakout above that range.
This is exactly how each of the previous waves began: national data obscuring the beginning of a regional wave. Last spring, despite confirmed community spread on multiple continents, everyone from President Donald Trump to NYC Mayor Bill de Blasio continued to downplay SARS-CoV-2. Last summer, despite clear signs of spread throughout the quick-to-re-open Sunbelt states, there was the infamous WSJ op-ed from Vice President Mike Pence “There Isn’t a Coronavirus Second Wave.” Last fall, when a clear wave was building across the Upper Midwest (i.e. the first place winter weather occurs), prominent epidemiologists such as Dr. Michael Osterholm were writing, on Sept 16th(!!) “America Needs to Lock Down Again.”
In the previous update, we saw how multiple states were experiencing sustained increases in confirmed cases, despite the national plateau. These trends have continued and there is a clear wave of confirmed cases across the Northeast and Michigan. Graph (top) generated with the CDC’s comparison tool and map (bottom) is from COVID Act Now.
A new springtime wave isn’t unique to the United States. As previous updates have covered, there are large waves across the entire Northern Hemisphere. Daily cases graphs for India, Italy, Canada, Japan, Poland, and Iran shown below. What seems to have happened is that for a variety of economic, psychological, and societal reasons, countries began re-opening before broad vaccinations and seasonality effects could combine to keep viral spread controlled.
This provides the key insight into the drivers of the surges across the Northern Hemisphere. In very broad strokes, all countries have approximately the same re-opening impulse and all have approximately the same seasonality effects. The critical difference and primary driver of current caseloads is vaccinations administered per capita.
Below is a graph of vaccinations dosed per 100 people for the six Northern Hemisphere countries shown above along with four Northern Hemisphere countries that are leading the way on vaccinations.
The countries with <20 vaccinations per 100 people are having waves, while the countries with >40 vaccinations per 100 people (below) are having continued declines, with a small increase in the United States.
Vaccination rate being the primary driver doesn’t mean it’s the only force at play. The notable exceptions are informative on seasonality effects. As said in the Feb 21st update, “R(t) [viral spread] is influenced by multiple factors, all of which are pushing it either upward or downward.” Seasonality research was already being published as early as June 2020 and with the large waves during the Northern Hemisphere winter, it should be clear that temperature and humidity affect the rate of viral transmission.
A few notable exceptions to the vaccination rate/trajectory of cases hypothesis: Chile, Spain, and Portugal (vaccination rates shown below). Despite having one of the highest vaccination rates in the world, Chile is having an extremely large wave of cases. Why? Chile is in Southern Hemisphere, thus heading into winter (likewise, essentially all of South America is having a large wave). Meanwhile, Spain and Portugal have below average vaccination rates but not experiencing waves like the rest of continental Europe. Why? The Iberian Peninsula is one of the warmest places in Europe!
If the United States is doing extremely well with vaccinations, why are we having a regional wave? The answer is a combination of above-discussed geographic effects, continued spread of variants (Michigan has the most confirmed cases of the ‘United Kingdom’ variant per capita), but also differences in vaccinations by age.
Both mobility data and credit card spending suggest a massive surge in re-opening, not to mention anecdotal evidence like Miami having to issue a curfew because of the large numbers of spring break travelers. But the United States does not have enough population-level immunity to have reached herd immunity, so it makes sense that we’re experiencing a minor bump in cases.
Combine that with the age-based case data from Israel (below) and it seems to suggest that the ‘risk-tolerant youth’ are fully embracing the re-opening trend and it is this cohort that is driving national case trends. Unfortunately, there is a delay in reporting the demographic data of cases to the CDC (that data can be found here and it will be important to monitor in the coming weeks). But data from nursing homes and long-term care facilities suggest cases are absolutely cratering there.
Since age has always been the number one risk factor for COVID-mortality and the United States has concentrated its vaccinations in the elderly, this fourth wave should be much less deadly than any of the previous waves. We’ve previously seen how deaths are lagged relative to both cases and hospital admissions, so we aren’t ‘in the clear’ just yet, but it is encouraging that daily deaths continue to trend downwards. This past week, the seven-day average for daily deaths fell below 1,000 for the first time since early November.
While acknowledging the multiple factors at play, the primary driver really is vaccinations. Vaccinations is how we end the pandemic. Fortunately, the United States continues to excel at vaccinating. Credit must be given to the Trump administration for starting and funding Operation Warp Speed, to the Biden administration for continuing and accelerating the pace of vaccination, and to the countless state and local public health officials and medical professionals who are the ‘boots on the ground,’ and doing the hard work of distributing and dosing each vaccine.
Vaccinations within the United States continue to scale. The seven-day average for daily vaccinations is 2.62 million, a record high. Over 136 million total shots have been administered, with 27.0% and 14.7% of the population having one and two shots, respectively.
Unfortunately, our vaccine reserves continue to build. There are 40.8 million vaccines that have been distributed but not administered, a record high. There needs to be much less focus on eligibility requirements and much more focus on ‘getting shots in arms.’ Even if no more vaccines were delivered, we could continue vaccinating at our record pace for ~15.5 days.
The Biden administration has directed all states to fully open vaccinations to *all* adults by May 1st. Fortunately, many states have taken the initiative and shifted that timeline forward (below). Even though this map is only a few days old, many states have accelerated their timeline even further. For example, Minnesota will open vaccination to all adults this Tuesday and California shifted their date to April 16th.
The United States is at the beginning of a fourth wave. With vaccinations continuing to scale and seasonality effects continuing to improve, we should expect this wave to be smaller and less deadly, despite re-openings continuing unabated. COVID-19 remains a serious disease and the variants-of-concern continue to spread within the United States. Please continue to wear a mask, physically distance, and schedule your vaccination appointments for the soonest possible date. All three vaccines authorized in the United States are highly effective at preventing symptomatic disease and completely effective at preventing serious disease and death. We’re in the final innings of the pandemic; let’s crush this damned virus.
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