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State Of The
Pandemic
Projections By The
Institute For Health Metrics And Evaluation Reveal We Are Nowhere Near
The End
Widespread
Availability And Uptake Of Vaccine Appear To Be Many Months Away
The epidemic in the US
is far from complete and, even in the optimistic scenario of herd
immunity kicking in after 40% rather than 60-70% cumulative infection,
the country would be less than halfway through the pandemic even three
months from now on January 1, 2021, according to the Institute for
Health Metrics and Evaluation (IMHE).
Likewise, IMHE
estimates the epidemic globally is also very incomplete and the larger
world will be less than one quarter through the pandemic on January 1,
2021. In short, we have seen only a fraction of the burden of disease
to be experienced from this pandemic unless drastic change through
vaccination or treatment is brought about.
Fatigue
Even the social
distancing and other mitigation activities we have that are known to
work may become less effective through decreased use. There is concern
that fatigue with non-pharmaceutical control measures is setting in in
the US and elsewhere and that erosion of public support may lead to
adoption of more hands-off approaches. These would potentially create
herd immunity to eventually slow or halt the spread of the pandemic
virus, however, letting nature take its course would extract a heavy
price in terms of morbidity and mortality. This is because relatively
low percentages of the populations in the world, with few exceptions
such as Ecuador and Mexico City, have been infected.
Herd Immunity
Recently, unproven
claims that herd immunity may occur at much lower levels such as 40%
or even 20% have appeared on social media, according to IHME. The
reasons cited for a lower threshold are the role of super-spreaders,
non-random mixing in less dense populations, non-overlapping social
networks, and some prior coronavirus immunity. The fatigue with
control measures is coming just at a time when more robust social
distancing measures would be called for in the Northern Hemisphere to
counter the anticipated upsurge in cases by January 1, 2021. For
example, another lockdown is being urged for the United Kingdom where
cases are doubling.
Toll With Herd
Immunity
Even assuming herd
immunity could kick in at 40% in the US, IMHE’s analyses of
seroprevalence data and infection fatality ratios suggest the US would
eventually experience over 800,000 deaths to get to that point. This
projected number increases to over 1,000,000 deaths if herd immunity
requires 50% seroprevalence and approximately 1,300,000 deaths if 65%
seroprevalence is required. These numbers of deaths are approximately
2-7 times larger than the number of deaths that have already
occurred in the US.
Global Toll
Globally, making
similar calculations for herd immunity predicts the world would see
10-13 million deaths before the pandemic extinguishes itself.
Currently, just under 1,000,000 deaths have been recorded worldwide.
Needless to say, both sets of projections could be reduced
considerably with widespread use of effective vaccines or new
treatments. However, as we read less about when a vaccine or vaccines
might be “available” and more about but when a vaccine or vaccines
might be in “widespread distribution”, the return to normalcy may be
months or even years away globally, and this will be reflected in a
sustained number of excess deaths when compared to the years just
prior to 2020.
End of the Pandemic?
A recent article in
The Atlantic made this point forcefully by asserting that “the sublime
post-pandemic period that so many are longing for will likely not
arrive at once like a clock striking midnight on New Year’s Eve….As a
matter of epidemiology, there’s no clear cut criterion that determines
a pandemic is over. You can’t sign a treaty with a virus, so we have
to settle for a kind of cease-fire, Columbia epidemiologist Stephen
Morse told the Atlantic.
Near Term Projections
The IMHE has lowered
its projection of US deaths by January 1, 2021 from 415,000 to 378,320
because of steeper than expected declines in deaths in several states.
Daily deaths have been steadily declining reaching 650 per day
recently, but COVID remains the second leading cause of death in the
United States. And with the expected seasonal surge later this year,
IMHE anticipates over 3,000 deaths per day by the end of December.
Preventable Deaths Now
Approximately 180,000
additional deaths are projected to occur between now and January 1,
2021 with almost two-thirds of these (115,000) able to be prevented if
mask use could increase to 95%. Such an achievement appears unlikely
since global mask use defined as the percentage of the population that
reports always wearing a mask when leaving home remains constant
globally at about 60% and is below 50% in the US.
Global Near Term
Projections
IMHE believes it is
likely that global deaths will increase from approximately 5,000 per
day now to over 30,000 deaths per day in December. Hundreds of
thousands of lives could be saved with increased mask use worldwide
just over the next few months, that is, preventing approximately 43%
of the deaths expected between now and the end of the year. ■
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