COVID-19 Odds

Quantitative analyses on the global coronavirus pandemic

Taiwan, Singapore and Japan – 3 Different Delta Fates

For the first 15mo of the global pandemic, many analysts had held up Taiwan as an exemplar for how to handle a pandemic.  They had experienced only a few hundred well-monitored cases and only 7 deaths from COVID-19 for 15 months.  During this same period, Singapore also did very well.  They weren’t able to avoid infections with a high number of guest workers in a fast-growing City-State but they kept their case fatality rate low (CFR = 0.06%) due to a young population and a good healthcare system.  Japan, being a larger country with many International ties experienced all the travails of the global pandemic in 4 waves matching more or less those of the USA and the rest of the world.  They had a CFR that was near 2% – quite good for a population with high median age.  The fates of the 3 have diverged dramatically with the arrival of the Delta variant this Spring. 

Taiwan’s island nation status allowed them to isolate themselves from the storm raging outside in 2020.  Then they relaxed their vigilance and allowed a few airline personnel to come into contact with Delta and then they rapidly lost control.  Moreover, they got too complacent and did not push vaccinations very hard so much of the country was unvaccinated when Delta hit and Delta hit hard.  The CFR for Taiwan for Delta is a horrendous 5.3% – a tribute to the contagiousness and virulence of the Delta and a sign of how unprepared Taiwan really was to fight a serious pandemic. 

In Singapore, they were able to fend against Delta fairly well until just 2 months ago – then Delta hit hard.  Cases soared and now deaths are soaring as well. The CFR appears to be 0.3% or 5 times worse than prior but could well be 10X worse when this infection wave passes.  Curiously Singapore is one of the better-vaccinated countries in the world so that many of these cases and deaths must be breakthroughs.    

Finally, for Japan their Delta invasion came coincident with the Olympics.  Cases edged up in the weeks before the Olympics start as athletes arrived to prep for the Olympics and peaked within 10 days after the end of the Olympics.  At the peak, cases were nearly 3 times higher than for any prior peak.  However, it looks like CFR will be just 0.32% for this fifth wave.  How did Japan manage to do better against the Delta than prior variants when they had experienced CFR = 2.0% in wave #4?  One possible answer is that the median age of infectees had dropped for the Olympics.  Japan was just beginning to vaccinate its people and it started with the older, more vulnerable part of the population who were by nature more cautious and masked or stayed home.  The real answer may not be known for a few more months, though.

Against the Delta, the good turned in poor performances and the bad turned in better performances.  The Delta variant continues to confound scientists and governments.   Some are saying that if a highly vaccinated and masked Singapore can experience a Delta surge – no country is safe. The most prudent approach is to assume that with the Delta we are dealing with an entirely new contagion that requires high vigilance and much more study.  

Save Our Children From The Ravages Of COVID-19

The COVID-19 pandemic had been relatively mild for children in 2020.  In the early days, schools were shut and kids were sent home to learn remotely.  Later when people found out kids were not as susceptible to serious illness from SARS-CoV-2, schools reopened and in-person learning was slowly restored with strong mitigation measures instituted.  Pediatric hospitalizations (red curve in the figure below) increased last Fall but not too badly –running near 1.2% of adult hospitalization at the peak around the New Year.  Late Spring 2021 with Delta edging onto the scene it became obvious that kids were more susceptible to this more contagious and possibly more virulent variant.  Epidemiologists warned that school reopening without strong mitigation measures could lead to disaster and yet ironically more governors and parents went the opposite direction and eased mitigations.  The end result is that pediatric hospitals were swamped and more kids suffered needlessly with MIS-C and other long COVID illnesses as pediatric hospitalizations are now at record levels = 2.4% adult hospitalizations.     

Why do we say needlessly?  Because there are now proven mitigation measures that could have reduced the toll.  Kids 12 and over and all staff could and should have been vaccinated.  All kids and school personnel should have masked up indoors.  Improved ventilation techniques such as HEPA filters could have been applied.  Rapid testing could have been given to kids on a regular basis, especially those without access to vaccines.  Even adopting some of these measures would have permitted in-person instruction to continue with minimal interruption.  As it was, schools tried to reopen without mitigation measures and were forced to close or quarantine a large number of students – interrupting their education and producing a worse result than if they had just stayed with remote learning. 

Could all this have been avoided?  In California, schools reopened successfully with many of these mitigation measures in place.  The difference between Texas (red curve in the figure below) and Florida (blue) with obstructionist governors, and California (green) with a governor that follows the science is striking. 

Kids can return to in-person learning safely and stably.  Families with elderly grandparents or immunocompromised parents can breathe easier knowing their kids are safe and they won’t be bringing home the virus.  All it would take is for a governor to show true leadership and do his primary job of protecting the lives and livelihoods of his constituents.  

COVID-19 Reporting Issues – Bigger than FL and CDC

COVID-19 data tracking and reporting have been problematic from day 1.  Outdated systems and procedures made it difficult to understand the severity of the pandemic in its early days and handicapped the US efforts to control it.  President Trump in a fit of pique and for political reasons decided to bypass the Center for Disease Control (CDC) for COVID-19 reporting and shift it to another department in Health and Human Services (HHS) on July 15th, 2000.  This has turned out poorly because while the CDC had problems, the HHS had no experience with tracking and reporting infectious diseases.  While this helped Trump in the short term politically because the HHS was more willing to alter the data to fit the President’s message it hurt the US pandemic response long term.  The President should have spent money on improving the existing CDC system instead of building another parallel system to monitor COVID-19. 

Have things improved in 2021?  The recent miscues in reporting cases and deaths from the Florida Department of Health (FL-DOH) to the CDC say no.  It turns out that there is another way that FL COVID-19 deaths were tracked by the HHS on its HealthData.gov website.  Since July 2000, HHS has compiled COVID-19 deaths as reported by all the hospitals in the USA.  In its early days it was incomplete – possibly because many COVID-19 deaths occurred outside of hospitals – in nursing homes, prisons, private homes, etc.  But for the current wave, HHS has been tracking FL deaths better.  HHS (red curve in the graph below) appears to tracks about 90% of all deaths compared to the blue curve which tracks deaths on an actual date basis as now reported to the CDC.  It tracks quicker with just 2-3 days delay from the actual date of death – unlike the green curve which counts deaths as actually reported but delayed by 2 weeks of massaging (formerly reported by the FL-DOH to the CDC).  It tracks the actual shape of the growth in death that cursory examination of the blue curve would distort.  So if the Governor of Florida was trying to manage the narrative he forgot that the HHS death time series would have undercut that story – deaths are really soaring in FL as they are in TX, GA, and most other states.   

So is the HHS system better than the HHS system?  No, because while it has the best hospitalization data its data on COVID-19 cases and deaths are incomplete. We had actually begun this study to see whether there were as many deaths occurring outside of the hospital system as there had been in prior waves.  The fact that there haven’t been is somewhat surprising (perhaps due to the ferocity of Delta), but does not obviate the need for the more complete count done by the CDC.  Even that could be improved since substantial evidence exists that deaths in excess of what is normally expected every year have occurred above and beyond what the CDC has counted as confirmed and suspected COVID-19 deaths. 

The USA should be investing in a single centralized data system that captures accurate, timely, and consistent infectious disease data from all states.  Data validation systems (using A/I and machine learning) can identify attempts to pass inconsistent or incomplete data so that only clean data is presented to the public and given to scientists for detailed analysis.  CDC should provide state-of-the-art data extraction and reporting tools for that one system instead of building two expensive half-baked systems.  Trying to manipulate or manage the data will ultimately be futile creating short-term confusion and long-term distrust of data and science and the government.   

Delta Variant is More Contagious And Appears to be More Virulent

Many studies have now shown that the Delta variant is about 2.3x more contagious than the original SARS-Cov-2.  Some people suspect that it could also be more deadly but there is no clear evidence for this.  Much anecdotal evidence points to there being more young adults and kids being seriously ill and hospitalized during the latest Delta wave.  But are there more people hospitalized and dying from Delta than before? 

Are cases resulting in more hospitalizations?  For the period before 6/1/21, 8.1% of all COVID-19 cases in Florida (FL) required hospitalization (CHR = Hospitalizations/Cases).  For the last 100 days when Delta began to dominate, 9.3% of all cases resulted in hospitalizations.  You may have noticed in the graph below that this trend that had brought the hospitalization rate briefly over 10% (note that the hospitalization rates are scaled at 1/10th the scale of cases) has reversed over the last 3 weeks. 

The reason for this is that since schools reopened more pediatric cases have been identified and even though they do get hospitalized they do so at a much lower rate than older adults.  This tends to drag the overall CHR lower.  We used to be able to calculate CHR by age but since FL went to weekly reporting with far less detail it has been difficult to get CHR by age.  An alternative is to measure total new hospitalizations/capita/year versus age.  Delta produces higher hospitalization rates because it spreads faster and when it does infect, it produces more hospitalizations for most groups biased toward the younger (red curve below). Furthermore, if we adjust for vaccination status (~10% for the period covered by the blue curve and 50% for the period covered by the red curve) the danger of the Delta variant is even more pronounced. 

Another way to look at the severity issue is to calculate the lagged Case Fatality Rate [CFR = deaths/(cases 3 weeks prior)].  The curve below shows a marked increase in CFR to near 2.0% from a 2021 average of 1.3% beginning in June with an apparent drop-off in August.  Recently it has moved back up to near 1.6%.  This is surprising given that the median age of confirmed cases has dropped due to kids being infected from schools reopening dangerously.  Moreover, we would expect CFR to drop over time as more people get vaccinated since the CFR for vaccinated people is expected to be lower and even lower still for those boosted (this is what is observed in the UK and Israel). 

The age effect for CFR is very strong with older people much more susceptible to deaths than younger folks.  This can be seen in the graph below where CFR by age for the life of the pandemic in FL is shown in blue.  Similar data for all deaths reported during the 5 week period from 8/5-9/9 is shown in red.  You can see that the red curve is higher for all age groups under 65 years old.  This seems to suggest that the Delta variant is more deadly.  The 65+ age group is far better vaccinated (87%) than any others in FL so a higher percentage of these deaths are probably breakthroughs with lower CFR than for unvaccinated of the same age. 

Given that all this data suggest that the Delta variant is more contagious AND more virulent, especially for innocent kids, we need more accurate, timely, and consistent information from all the states, the CDC, and HHS – not less.  It should be criminal to withhold such data from the public, the President, and the scientists who are desperately trying to understand SARS-CoV-2 better so we can control the pandemic.  

Florida’s COVID-19 Reporting Change Has Major Consequences

Our blog post about the major change in Florida’s COVID-19 reporting to the CDC has developed into a national story with partisan biases.  A couple of days ago the Miami-Herald “broke” a news story that claimed Florida changed its COVID-19 data recently – something that I had worked with a Sun-Sentinel reporter to break 18 days prior.  Now the story has been picked up by MSNBC, the Wall Street Journal, and other national news services.  However, none of these stories have addressed the full impact of Florida changing COVID-19 cases and deaths from date of reporting to actual date of occurrence.   

1.     While technically correct the new FL method is only used by a few other states to report their deaths to the CDC.  Contrary to the WSJ article’s claim, TX is not using the FL method – or if TX is using the new method they only have a 1-2 day lag in recording deaths. The figures below show how CDC currently stores and displays FL and TX death counts.  As you can see FL death counts show a peak two weeks ago and a drop-off to near zero today.  While TX death count curve shows a steep rise to near-record highs.  The FL data for the last 4 weeks will be continually adjusted upward over the next 4 weeks – delaying accurate information for 4 weeks. 

2.     Allowing some states to report one way and other states to report a different way is a basic Data Science 101 error by the CDC.  You add apples to oranges and you get a meaningless fruit salad.  The CDC according to the WSJ has conceded that some states report the FL way and others such as TX report the traditional way. 

3.     Some states like CA are using actual dates reporting but because they update their data daily, databases and modelers can choose to use either time series in their models.  For FL, though, the wrong death count could be in the system for 7 days (eg. JHU still shows 43,979 as the total cumulative death that was reached and reported 6 days ago for FL). 

4.     If the CDC adds all the states up for the USA total, it distorts the picture of USA death counts and confuses the public and data scientists trying to forecast and advise POTUS.  FL accounts for ~20% of the US total deaths.  The new FL method understates deaths for the last 3-4 weeks which are used by many models to predict future death trends causing them to understate their forecast and causing POTUS to react too late.

Just as good military intelligence is essential for the conduct of a successful war – accurate, timely, and consistent information is essential for successfully winning the war on SARS-CoV-2.  USA intelligence on the COVID-19 pandemic had been poor and has not improved much this year.  Inadequate testing resulting in very high positivity rates, too little genomic testing to understand Delta’s contagiousness and ferocity, dropping breakthrough tracking just when vaccine efficacy may be waning, and switching reporting methodology and allowing states to drop daily reporting in the middle of a pandemic are just a few examples that could cause the USA to lose the war.  The CDC should set the standards for consistent daily reporting and help all states to achieve this.  Viruses do not respect state boundaries and the CDC should not let states dictate what information states give them.  When COVID19 cases are doubling as quickly as every 3 days in some jurisdictions earlier this summer, cases can grow a thousandfold in a month and quickly swamp hospitals causing unnecessary deaths.  Timely, accurate, and consistent information is key to making the right decisions to mitigate the spread and win the war.  

Two mRNA Vaccines Are Not the Same

In the early days of the COVID-19 mRNA vaccine rollout in the USA this year, vaccines were in short supply and people had no choice as to which vaccine to try.  Both two-dose vaccines from Pfizer and Moderna seems to have similar 95% efficacy against serious disease.  Recent studies are revealing significant differences between the Pfizer and Moderna vaccines. 

Moderna has nearly 3X the amount of active ingredients in Pfizer: 100mg vs 30mg.  Moderna created 2.6X more antibodies in patients than Pfizer – with both being negatively correlated with patient age and both declining exponentially over time.  The higher amount of initial antibodies allow Moderna to be more effective and durable against the Delta variant than Pfizer: the risk of a breakthrough case was 2X lower.  While Pfizer is recommending a booster 6 months after the second shot, Moderna is recommending a booster before this winter.  Moderna’s proposed booster has only 50 mg of active ingredients, but it is still proving to be highly effective in phase 2 clinical trials to date.   

As for side effects, a greater percentage of participants who received the Moderna vaccine reported reactogenicity: 82% vs 69% for Pfizer.  Many people (13%) taking Pfizer reported side effects with both doses that sidelined them for 1-2 days.  A small percentage (0.6%) reported symptoms severe enough to require a visit to the ER, and only 0.25% required hospitalization.  It is believed that serious side effects with Moderna are also <1%

If you are immunocompromised and probably did not get full protection from two shots – get your booster shot now unless you had severe side effects.  If you’ve had severe side effects after the second Moderna wait a few weeks for the 50 mg Moderna booster.  Otherwise, on September 20th, all Americans should be eligible for a booster shot.  Get it to improve your protection against severe COVID-19 illness.  Always mask up and social distance for additional layers of protection.     

Some Governors Are Endangering Kids and Prolonging the Pandemic

Many governors in the USA are insisting that they cannot mandate vaccines or mask usage (as in GA), or are actively obstructing localities that try to do so (FL and TX).  Their claims rely on rampant misinformation that kids do not get COVID-19 – or that if they do, they get very mild cases and do not spread it easily, and rarely do they die from it.  This was questionable earlier this year with the initial variants and has become very misleading in the last two months as the extremely contagious and ferocious Delta variant has spread to constitute 99% of all cases in the USA. 

It is increasingly clear that the Delta can and does seriously infect school children, especially those under 12 who cannot be vaccinated yet.  Recent anecdotal stories from Florida have raised alarm and now strong statistical evidence has emerged that reopening schools without mitigation measures may be extremely dangerous to the health and futures of millions of kids while also encouraging the continued spread of the SARS-CoV-2 among all Americans. 

The table below from the Florida Department of Health (FL-DOH) weekly report captures the case trend by age group in FL over the period of 7/29 – 8/19, a period when many schools began to reopen in FL.  Columns 2-4 show the weekly case counts per 100,000 people for the weeks ending in 8/19, 8/12, and 8/5.  These are all extremely high although the over 65 group is below average due to their well-vaccinated status (85%).  The last two columns show the percent change from week to week.  As expected cases were still soaring in the period from 8/5 – 8/12 for every age group with as high as a 23% increase for the under 12 age group.  With schools reopening the virus has continued to surge for that age group – up by 22% for the week 8/12 – 8/19.  Middle school and high school student infections grew by 16%.  Interestingly, this wave appears to have peaked for everyone else.  This is somewhat expected since Delta surges are extremely contagious and fast-growing but they also tend to burn out rapidly after reaching a peak infection of about 100 per 100,000 per day.  At this stage, exponential growth stops as it did in the UK. 

What about the more dangerous outcome of Delta – how fatal is it?  The answer is slowly beginning to emerge as deaths take 2-4 weeks after infection to resolve and then several more weeks to be reported.  The following table from FL-DOH shows that the case fatality rate (CFR = deaths/cases) from COVID-19 is highly age-sensitive with a CFR about 100 times higher for the oldest group (>65 yrs old) than the younger groups (<30 yrs old) over the 19-month span of the pandemic in Florida (column 4).  However, the strong age dependence has evolved with the arrival of Delta.  Death counts and death rates have increased for all age groups but most significantly for the young.  For those age16-29 years old, the lagged CFR [=deaths/(cases from 3 weeks prior)] has increased from 0.03% to 0.17%, or nearly 6-fold.  For middle-aged adults 30-49 years old, it has more than doubled.  Overall CFR has remained near the life-to-date value of 1.4%.  We need to accumulate more data to ascertain how much deadlier the Delta is than the original and earlier variants.  As more people get vaccinated, we expect the CFR to improve.  Unvaccinated kids and young adults will remain big carriers of the disease unless schools adopt stronger mitigation measures and they will also serve to lower the overall CFR.

This early data makes it clear that Florida’s current wave could have peaked already if the governor had not poured more fuel -misleading information – on the fire and supplied more kindling – kids.  Moreover, kids are much more likely to die from Delta than from the original SARS-CoV-2.  Along with the uncertain but potentially debilitating effects of Long-COVID, this makes the Delta variant a major threat not only to the wellbeing of millions of children but also to every Floridian.  Prolonging the contagion increases the possibility of even more dangerous variants developing in millions of Americans that continue to be infected each week.  

COVID-19 Death Counts Reporting in FL Gets Less Transparent

The Florida Department of Health (FL-DOH) convinced the CDC to accept an alternative method for reporting COVID-19 cases and deaths this week that made things less transparent and more confusing at a critical junction of the pandemic.  The FL-DOH has done well in tracking actual and reported dates for deaths and cases but now it has switched the two up in its reporting to the CDC and the public.  The CDC appears to have accepted the new actual date reporting from FL without questions or explanations while most of the other 49 states are still sending the CDC “as reported date” information.  At the end of the day, the two data series wind up in the same place because cumulative cases and deaths must total to the same numbers at all times, but in the interim, there is the potential for misleading conclusions and bad policies. 

report dateCum casecalc diffpre wk casecum deathcalc diffpre wk deaths
12-Aug      2,877,214      151,764      151,415      40,766      1,071       286
5-Aug      2,725,450      134,751      134,506      39,695       616       175
29-Jul      2,590,699      110,724      110,477      39,079       409       108
22-Jul      2,479,975        73,166        73,199      38,670       282         78
15-Jul      2,406,809        45,449        45,604      38,388       231         59
8-Jul      2,361,360        23,747        23,697      38,157       172         32
1-Jul      2,337,613        15,684        15,978      37,985       213         48
25-Jun      2,321,929        11,048        11,873      37,772       217         44
18-Jun      2,310,881        10,095        10,629      37,555       290         43
11-Jun      2,300,786        12,157      37,265         40

Source: The bold numbers are those reported by the FL-DOH (http://ww11.doh.state.fl.us/comm/_partners/covid19_report_archive/covid19-data/)

By going to the actual date of occurrence reporting, data for the previous days are continually updated in a non-transparent way.  For example, the weekly FL-DOH report says the previous week’s deaths total 286 for the week ending August 12th (row 2, column 7 in table above).  But the week’s total deaths can also be calculated by subtracting the previous week’s cumulative total (39,695) from the current week’s cumulative total (40,766) to get 1,071 additional deaths reported for the week ending in August 12th.  The FL-DOH’s 286 is the actual number of people who died during that week AND were reported for that week, but this number needs to be continually adjusted as deaths sometimes take 2 months to verify in FL.  Eventually, the 286 will grow to 1,000 – 1,100 as late death reports drift in.  Similarly for FL-DOH to say the death count is 29 for August 12th (see last red dot on the graph below) may be technically correct but extremely misleading.  Deaths in FL have not gone down over the last two weeks but are in reality rising.  Every day this 29 number will grow but the growth may be concealed from public view.  Without proper explanation, the public will be misled to draw the wrong conclusion about how to slow or end the pandemic.  

The green curve would cause citizens and their government to become more alarmed and more vigilant about adopting sensible mitigation measures such as vaccines, masks, and social distancing.  Rising cases and hospitalizations should have already convinced citizens to do the right thing, but many still argue that until cases result in death they are not concerned.  The red curve might lead the casual observer to say things are not so bad and the government to say that further mitigations are not necessary.  Because pandemics grow exponentially fast, every day’s delay in action now can result in hundreds of dead Floridians. 

The problem is not confined to Florida because Florida has accounted for up to 20% of all US cases and still accounts for 20% of all US hospitalizations, it has an outsized effect on total US numbers.  The declining death count in FL would soften the rising death count seen in every other state in the union, causing the CDC and the US government to adopt bad public health policies.  It could lead other states such as Texas to say “if FL can do nothing and in fact still obstruct public health policies and do well maybe we can do the same thing”.  Texas COVID-19 cases, hospitalizations, and deaths are soaring.   Worse, they may adopt this Florida method of suppressing recent death counts and make themselves look better.   (Something funky happened in California this week but it seemed to have been a one-time restatement; their death counts have resumed rising.)  So we humbly request that the CDC reconsider this change and make Florida report deaths in the same way as every other state which would allow Americans and scientists access to the latest information in the most transparent and uniform fsdhion – otherwise, they must carefully explain why the entire data series needs to be downloaded every day and preserved to get the full picture 

COVID-19 Death Counts in the USA are Rising

President Biden and the CDC are hoping that the US COVID-19 death rate will be better for this current surge.  We are optimistic but have doubts.  The reasons are complex.  For one, the US continues to test much less thoroughly than other best-in-class countries such as the UK.  Thorough testing can identify and stop outbreaks before they become serious surges.  Moreover, identifying a higher number of asymptomatic and mild cases causes the measured case fatality rate (CFR = deaths/cases) to improve since the denominator increases and the ratio decreases. 

In the UK, the CFR appears to have improved significantly from 2.1% for the last wave in January to 0.3% for the current Delta surge.  Part of the reason for the improvement is that the majority of Brits were vaccinated in early 2021 and the death rate for the vaccinated is much lower than for the unvaccinated. 

The US hopes that a similar improvement will be observed.  Unfortunately, this appears to be unlikely for a number of reasons.

1.     The vaccination rate has been slower and lower in the US than in the UK.

2.     The positivity rate is much higher in the US (~9%) than in the UK where it has stayed below 4% throughout this last surge.

3.     The hospitalization rate in the US has already begun to soar. 

4.     The CFR has shown little improvement in the US this year. 

This last point is crucial since it is the best predictor of deaths to come from cases and hospitalizations already in the pipeline.  Lagged CFR is calculated by dividing the average deaths for the past 7 days by a weighted average of cases for the previous 2 – 4 weeks.  Deaths usually take up to 20 days to resolve from case identification.  Then some jurisdictions take up to 2 months additional to report those deaths.  The graph below shows that after the initial confusion in early 2020, CFR improved dramatically and then stabilized around 1.5% for most of 2021.  The fact that it hasn’t improved over the last 12 months is rather disappointing.  It suggests that testing, tracking, and treatment of COVID-19 cases in the US has not improved in that time. 

In recent weeks the CFR has actually deteriorated due to the very contagious and possibly more lethal Delta variant catching an unprepared American population.  We expect the CFR to improve through the rest of the year for an unfortunate reason: the increasing prevalence of breakthrough cases as the effectiveness of vaccines begins to wane.  Since breakthrough cases are more likely to be mild, only a fraction ~0.4% will result in deaths. As more and more people get vaccinated the CFR could drop to the 0.3% seen in the UK.  We can only hope this happens soon.  In the meantime get the vaccine if you haven’t yet, get the booster if your last shot was more than 6 months ago, and wear a mask and social distance as much as you can.  

COVID-19 Breakthrough Deaths are NOT Rare

The Delta variant of COVID-19 is a very contagious and virulent beast.  When better data is required to understand this rapidly evolving virus CDC tracking of COVID-19 cases has gotten worse.  For breakthrough cases due to the Delta variant, only the bare minimum is available.  Nevertheless, they do track total cumulative weekly hospitalizations and deaths in the US (with many caveats).  These data allow us to track incremental weekly data by subtracting the previous cumulative total from the current week’s cumulative total.  The trend is disturbing.

Week EndingCum BK HospitalCum BK Deaths7-day BK Hosp7-day BK Deaths7-day total Hospital7-day total Deaths% of hosp% of deaths
8/2  7,101  1,507    862     244  10,000    2,868   8.5%    8.5%
7/26  6,239  1,263    325     122    6,000    2,133   5.4%    5.7%
7/19  5,914  1,141    725       78    9,000    1,978   8.1%    3.9%
7/12  5,189  1,063      
7/19-8/2   1,912     444   25,000    6,979   7.6%    6.4%

Source: CDC (https://www.cdc.gov/vaccines/covid-19/health-departments/breakthrough-cases.html

Cumulative breakthrough hospitalizations (column 2 in Table above) and cumulative breakthrough deaths (column 3) in the table above are not very useful for analysis since they cover a long period of time when there were only a few fully vaccinated Americans and few Delta variant cases.  For the original and early variants, the mRNA vaccines were extremely effective against infections and near 95% effective against hospitalizations and deaths.  But the Delta variant is much more contagious and possibly more virulent.  Given this uncertainty, it is very important to track how the Delta variant behaves against vaccinated and unvaccinated Americans.  The most recent CDC data releases allow us to do this for the total US.  Columns 4 and 5 give us the 7-day totals for breakthrough hospitalizations and deaths, respectively.  These weekly totals were small and formed a small percentage of the total US numbers until 5 weeks ago when Delta cases started to soar in the US.  Overall breakthrough hospitalizations and deaths began to soar 4 weeks ago.  Over the 3-week period from 7/12 to 8/2, 6.4% of all deaths were breakthroughs (column 9) and an estimated 7.6% of all hospitalizations were breakthroughs (column 8)in the US.  This is happening at a time when about half the US (49.6% as of 8/2) was fully vaccinated and about 83% of all COVID-19 cases were Delta (as of 8/2).  If the mRNA vaccine is 90% effective against death and if the same number of unvaccinated and vaccinated Americans were exposed to SAR-CoV-2 Delta over this time period we would expect only 5% of all deaths to be breakthroughs.  The fact that it is now above 5% is quite troubling.  All else being equal – a necessary assumption in the absence of disaggregated data – 8.5% breakthrough deaths last week implies vaccine effectiveness of 83% against COVID-19 deaths. One factor that may make this ratio high is whether other mitigation factors were employed by the unvaccinated such as consistent mask-wearing or social distancing that lowered the infection rate for this group.  If masks turn out to offer better protection than the vaccine against Delta infection then more unmasked vaccinated people would get infected increasing breakthrough deaths.

Furthermore, the trend has been worsening.  As Delta cases approach 100% of all cases we expect these breakthrough deaths to increase. Of course, as more Americans get vaccinated, the percentage will increase even further toward 100%.  Currently increasing percentages might mean that the protectiveness of the full vaccine may be losing efficacy.  Both Pfizer and Moderna have sought authorization to administer booster shots but the FDA and the CDC are balking, possibly for political and messaging reasons.  This is absolutely unacceptable, particularly for the immunocompromised.  Israel has now authorized booster shots, and they track variants and breakthroughs better than the CDC.  The FDA should also give full approval for the vaccines instead of dragging its feet.  The CDC must begin to track breakthrough cases with more timeliness and more detailed segmentation.  They should view this outbreak as a new spike that requires thorough study and vigilance – testing, tracking, and applying the full arsenal of mitigation measures. Loosening the mask guidance on May 15th was dangerous.   Declaring victory against COVID-19 on July 4th was premature.  Calling this a pandemic of the unvaccinated is an oversimplification that leads to incorrect behavior.

Every American must mask up to reduce infections, vax up to save lives.  

Page 1 of 11

Powered by WordPress & Theme by Anders Norén