The Same Winter/Summer Pattern We Saw Last Year Re-Emerges
As we expected, COVID-19 cases have dropped sharply in recent weeks in the Southern states that were hotspots in July and August. In Florida, new infections fell from a daily seven-day average of about 22,000 in mid-August to 5,500 on Sept. 29; in Mississippi, from 3,600 to 1,100; in Louisiana, from 6,000 to 1,000. Because testing has risen back to the January 2021 levels all over the country, these case rates paint a more accurate picture of the ups and downs of infections in the South.
Meanwhile, however, cases are climbing in more northerly states like Wisconsin (up 33% in the past 14 days), Alaska (up 84%), North Dakota, Minnesota, New Hampshire, Maine, and Vermont.
This is the same pattern we saw a year ago. As the weather cools off, people in the South go outdoors while in the North residents go indoors, and indoors is where the SARS-CoV-2 virus spreads more readily and rapidly.
Vaccination rates undoubtedly affect infection rates. We noticed last week that all 10 states with the highest number of COVID cases per 100,000 residents had fully vaccinated rates that are below the national average of 55%, while 9 of the 10 states with the lowest COVID case rates had fully vaccinated rates above the national average. But, with the Delta variant now responsible for 99% of infections, vaccinations don’t tell the whole story.
For the U.S. as a whole, the daily average of COVID cases on Sept. 29 for the seven preceding days was 113,000, down 26% from two weeks earlier and less than half the all-time record set in January. Hospitalizations have peaked, and deaths appear to have reached an apex as well. But all this is likely to be temporary.
The short history of COVID indicates that winter is the cruelest season because nearly all of America moves inside. What’s disturbing is that some of the cooler states are already far ahead of their case rates from last year. For example, Wisconsin on Sept. 25, 2021, had a seven-day average of 3,300 infections, a one-third increase over the same date last year. In Montana, cases are triple where they were a year earlier; in Minnesota, more than double. In Vermont, there were 194 average daily cases on Sept. 29; precisely a year earlier, there were just 4.
Even worse, hospitalization rates have increased, evidently because of Delta. In Idaho, hospitalizations reached a new high of more than 700 deaths daily in the last week of September. The record set during the last peak in January was 471. Deaths also set a record.
The CDC has appropriately called for “layered prevention strategies” against COVID-19. One of those layers, masking, received further validation from a study of Arizona schools published in the CDC’s Morbidity and Mortality Weekly Report (MMWR) on Sept. 24. Led by Megan Jehn of Arizona State University, the researchers examined infection rates in 999 schools in Maricopa and Pima Counties, which account for about three-quarters of the state’s population.
Of the schools, 519 had mask requirements and 480 did not. Between July 15 and Aug. 31, some 191 “school-associated outbreaks occurred.” Of those, 16 were in schools with early mask requirements, 62 in schools with mask requirements enacted a median of 15 days after school started, and 113 happened in schools without mask requirements. “The odds of a school-associated COVID-19 outbreak in schools with no mask requirement,” concluded the researchers, “were 3.7 times higher than those in schools with an early mask requirement.”
An Effective Layer of Protection Against Airborne SARS-CoV-2
Another layer that more and more schools – as well as health facilities, offices, theaters, and homes – are installing is a combination of ventilation (that is, the replacement of interior air with less dangerous outdoor air) plus a means of removing SARS-CoV-2 from interior air and surfaces. Ventilation itself is not enough, and the inadequacy of ventilation plus filters like HEPA was recently demonstrated in the Marin County investigation that was reported in the Aug. 27 edition of MMWR and that we related in a Sept. 14 COVID Solutions Bulletin Extra.
In that case, an unvaccinated teacher, apparently reading without a mask infected 55% of a class of masked students. The room had significant ventilation from open windows on two sides, plus “portable high-efficiency particulate air filters.” Those mitigation strategies failed, and it’s not hard to see why. A filter can capture pathogens only if pathogens flow into it, and many do not. A CDC study published in July, for example, found in a simulation that a HEPA filter reduced aerosol exposure by only 65%. But research shows that technology such as Advanced Photocatalysis attacks and inactivates pathogens that filters miss.
Photocatalytic oxidation, or PCO, is a general term for a technology that works by shining an ultraviolet bulb onto a coated surface, causing a reaction that turns oxygen and water in the air into the same oxidizing particles found naturally in the atmosphere. These particles then react with viruses and bacteria, inactivating them.
Common versions of PCO, however, create ozone and nasty secondary byproducts like formaldehyde, while proprietary versions of PCO that were developed later and are more advanced actually remove them. As a result, the CDC recommends a careful review of manufacturer data, including third-party research results. The U.S. Food & Drug Administration (FDA) clearance process requires proof that dangerous compounds are not formed during a device’s operation. For example, the advanced PCO technology of ActivePure, a Dallas-based manufacturer that recently installed thousands of devices in the Philadelphia public schools, provides a rare instance of FDA clearance in this field
Vaccination Potency Pre- and Post-Delta
More and more data have accumulated to show that the Pfizer and Moderna vaccines were effective at preventing the majority of infections and severe disease, as shown by hospitalization data before the Delta variant became widespread in the United States. Times have changed. Delta is “more than 2x as contagious as previous variants,” according to the CDC, and “some data suggest the Delta variant might cause more severe illness than previous variants in unvaccinated people.” Delta began appearing around April in the U.S., was found in a majority of cases the week of June 26 and in nearly all cases by the end of July. It now represents about 99% of infections.
A study published Sept. 24 in MMWR looked at 1,682 fully vaccinated subjects and 2,007 control patients between March and August and found that the Moderna vaccine was 93% effective against COVID-19 hospitalization; the Pfizer-BioNTech vaccine, 88%; Johnson & Johnson, 71%. And a study of about 5,000 health care workers, found vaccines “highly effective under real-world conditions.” Published in the New England Journal of Medicine on Sept. 22, the research concluded that, for complete vaccination, effectiveness at preventing infection was 88.8% with Pfizer-BioNTech and 96.3% with Moderna. But the study covered only the period from December 2020 to May 2021, so it missed Delta almost completely and undoubtably these numbers are now significantly lower.
Because the advantages of vaccination in preventing all infections have been blunted by Delta, it’s unlikely that the U.S. can avoid a winter surge. The recent past is not encouraging. The summer surge this year proved worse than last year’s. The lesson here is that, even with more than half of American fully vaccinated, we’re going to have to learn to live with COVID-19, at least for the near future and increase mitigation and safety indoors.
Meanwhile, despite the advent of boosters, vaccinations are on the decline. The daily seven-day average for shots (of any kind: first, second or third) at the start of September was 954,000; on Sept. 23, it was 683,000 (the peak day, in April, was 3.4 million). The New York Times calculates that, at the current rate, 85% of all Americans (including children) will have received at least one shot by June 13, 2022. By then, of course, the potency of initial vaccinations for those who received their shots at the peak vaccination period – February to May of this year – will have declined, perhaps significantly.
Vaccinations Decline in Effectiveness Over Time
The issue of arresting that decline through boosters has preoccupied Washington lately. On Sept. 24, Rochelle Walensky, the director of the Centers for Disease Control and Prevention (CDC) took the unusual step of overruling a recommendation by an agency advisory panel and instead endorsed booster shots for a wide range of Americans, including those in jeopardy because of their jobs, like health care workers, waiters and teachers. The advisory panel had backed boosters only for adults 65 and older and younger people at high risk because of underlying health conditions, excluding those with job-related and institutional risk.
The decision by the CDC Director comes on the heels of revelations that the effectiveness of vaccines against infection may drop sharply over time – again, probably because of the virulence of the Delta variant.
An article in the journal Nature on Sept. 17 stated:
Immunological studies have documented a steady decline of antibody levels among vaccinated individuals. Long-term follow-up of vaccine trial participants has revealed a growing risk of breakthrough infection. And health-care records from countries such as Israel, the United Kingdom and elsewhere all show that COVID-19 vaccines are losing their strength, at least when it comes to keeping a lid on transmissible disease.
That’s without accounting for the Delta threat either — and it’s clear that vaccine–induced antibodies do a worse job at recognizing SARS-CoV-2 variants compared with the ancestral strain of the virus. What remains unclear, however, is to what degree the immune system’s safeguards that protect vaccinated people against severe disease, hospitalization and death might be fading as well.
Research published as a preprint in mid-September by Nick Andrews of Public Health England and colleagues, using a sample of 4 million subjects, produced disturbing results. Vaccine effectiveness against infection for the Pfizer-BioNTech vaccine (with the brand name Comirnaty), which previous studies found in the 95% range a few weeks after the second dose, fell to 69.7% at 20 weeks and beyond; the AstraZeneca vaccine (Vaxzevira) fell to 47.3%. The “waning of vaccine effectiveness was greater for 65+ year-olds compared to 40 to 64 year-olds,”wrote the researchers.
What’s Happening to the Elderly?
That is an understatement. For this older group, effectiveness at 20-plus weeks against symptomatic infection from the Delta variant for the Pfizer-BioNTech vaccine dropped to just 55.3%; for AstraZeneca, 36.6%. Those figures compare to 69.1% and 49.4%, respectively 14 weeks after the second dose, so protection appears to decline rapidly.
In addition, the study found that longer intervals between first and second doses – around 8 to 12 weeks – “provide higher serological responses and increased vaccine effectiveness compared to the licensed 3-week interval for mRNA vaccines, thus potentially providing their populations with better longer-term protection. This is supported by our findings comparing short and long intervals in 80+ year olds in the current analysis.”
The researchers also found “that waning was greatest among individuals in clinical risk groups, suggesting that this group should be prioritized for boosters” – which is exactly what the CDC has now done.
Another study, headed by the CDC’s Srinivas Nanduri and Tamara Pilishvili, that sheds some light was published by MMWR on Aug. 18. Its subjects were residents of 14,917 nursing home and long-term care facilities, and it compared three periods: pre-Delta (March 1 to May 9), intermediate or partial Delta (May 10-June 20), and Delta (June 21-Aug. 1).
The results were dramatic and did not vary much between PfizerBioNTech and Moderna. Here are the combined data for the effectiveness at preventing infection of two doses of the two vaccines:
In other words, Delta produced a decline of nearly one-third in potency.
A separate study, by Kristina L. Bajema of the CDC and colleagues, published Sept. 17, covered a mixed pre- and post-Delta period, Feb. 1 to Aug. 6, and looked at COVID hospitalization rates at five Veterans Administration Medical Centers. The researchers found that, for persons aged 65 and older, vaccine effectiveness at preventing hospitalization was 79.8% compared to 95.1% for those under 65 – a major difference. The study noted that in past research “lower vaccine effectiveness among older adults had not previously been observed” and speculated that one reason might be that this study covered, in part, a period when Delta was rampant.
Comment Letters Criticize OSHA Proposal on Filters
With seniors especially vulernable, institutions with a proportion of elderly, including assisted-living facilities, are particularly in need of the best protection against the interior spread of COVID. But a recent proposal by the federal Occupational Health and Safety Administration (OSHA) aimed at health facilities is attracting serious criticism in part because it adds a burden to those institutions that seems unwarranted.
OSHA wants to improve ventilation and augment HVAC systems with MERV-13 (a measure of Minimum Efficiency Reporting Value) filters. We reported on this proposal in our last newsletter.
OSHA, a division of the U.S. Labor Department, has gained attention lately as the vehicle for the Biden Administration’s proposal to require workers at U.S. companies with more than 100 employees to be vaccinated.
On June 21 – months before the Biden vaccination proposal – OSHA published a broad Emergency Temporary Standard (ETS), with numerous requirements for dealing with COVID-19, in the Federal Register and asked for comments. Among the 460 comment letters were several that raised questions about the ventilation-plus-filters regulation.
Specifically, the regulations require….
.…employers who own or control buildings or structures with an existing heating, ventilation, and air conditioning (HVAC) system(s) must ensure that…all filters are rated Minimum Efficiency Reporting Value (MERV) 13 or higher, if compatible with the HVAC system(s). If MERV-13 or higher filters are not compatible with the HVAC system(s), employers must use filters with highest compatible filtering efficiency for the HVAC system(s). 1910.502(k)(1)(iii).
One of the comment letters, from Stacey Hughes, executive vice president of the American Hospital Association, called the emergency standard “vague, contradictory, and not necessarily helpful due to critical issues with MERV-13 [filters] when applied in a medical environment.” In a key excerpt, the letter stated:
The ETS requirements, by simply requiring hospitals to increase the filtration requirements without a system-by-system analysis and an understanding of potential performance of that filtration, could be harmful. This is because increasing filtration could have downstream impacts to the system that could alter the designed pressure relationships, causing the system to be out of balance, and potentially exposing immunocompromised individuals and others to harmful conditions.
In a joint comment letter, two Connecticut state legislators – Sen. Paul Formica, Senate Republican Leader Pro Tempore, and Democratic Rep. Jonathan Steinberg, House chair of the legislature’s Public Health Committee – agreed that “OSHA’s concern for the dangers of interior spread of the SARS-CoV-2 virus is absolutely warranted” but wrote that its “is misguided – both for health and economic reasons.” The legislators added:
In our view, the best course of action is an exemption stating that health care facilities are not required to install MERV-13 filters if they adopt proven anti-viral technology. Unlike filters, this technology inactivates the SARS-CoV-2 virus and other pathogens immediately and thoroughly.
The technology can be installed on existing HVAC systems or as stand-alone units. OSHA could simply state that antiviral devices that use FDA-cleared technology, such as those deploying advanced photocatalysis, may be used in lieu of MERV-13 filters in fulfillment of the ETS….
In recent years, critical health technologies have advanced significantly, and we believe the OSHA should adjust the ETS as a consequence. Antiviral devices, used in venues as diverse as California state hospitals, Philadelphia public schools, and Major League Baseball locker rooms, inactive virus that causes COVID-19 and can provide financial relief to health providers as they work hard to comply with protocols regarding interior air.
The Texas Assisted Living Association cited the costliness and impracticality of the promulgated regulations and said they were at odds with Texas Law and would have serious unintended consequences. The letter stated:
Suggestions to operate the HVAC to pull in the maximum allowable amount of outside air could easily cause problems for communities in Houston and along the Gulf Coast. Forcing HVAC systems to run at maximum capacity in hot, humid conditions will break down equipment faster and develop environments habitable to mold growth.
Jonathan Ellen, M.D., former head of Johns Hopkins All Children’s Hospital, wrote, “As a former hospital CEO, I know how important it is to have high-quality air filtration. But, we are always mindful of costs that make providing care more expensive.” He continued:
The system you’ve outlined would impose an undue financial burden on health care facilities because it would require the purchase of expensive equipment that would continue to generate high ongoing costs throughout the lifetime of the appliances. And we already know that the average age of hospital infrastructure is rising, with many facilities simply incapable of taking on broad-scale new technologies.
And if they’re too expensive or cumbersome to operate, many facilities will just avoid implementing effective filtration altogether, leaving patients, providers, and the public even more at risk.
Ellen wrote that cost-effective anti-viral devices “would effectively accomplish the same aims at a fraction of the cost, enabling more places like nursing homes and smaller hospitals to afford them.”
Other letters critical of the ventilation and filtering requirements, citing high expenses, came from US Renal Care and CareSpring Health Care Management, Kentucky and Ohio elder care facilities.
The agency will have to address these criticisms before rendering a final judgment. The idea of an exemption for facilities that install active anti-viral devices (especially with FDA clearance), as the Connecticut legislators and other commenters recommended, appears to be the best answer.
The Marin County Case
An Infected Teacher Reads to Her Class, and 55% of Students Come Down with COVID. Masking, Ventilation and HEPA Filters Weren’t Enough.
“On May 25, 2021, the Marin County Department of Public Health (MCPH) was notified by an elementary school that on May 23, an unvaccinated teacher had reported receiving a positive test result for SARS-CoV-2, the virus that causes COVID-19.”
So begins one of the most fascinating and important investigations we’ve read during this pandemic. It appeared in the Aug. 27 edition of the CDC’s Morbidity and Mortality Weekly Report (MMWR).
The report – whose lead author was Tracy Lam-Hine of the MCPH and the University of California at Berkeley School of Public Health – focused on the behavior of the elementary school teacher, the high level of student masking and distancing in the classroom, and the frightening rate of infection among those students.
But there is another lesson here that the report does not explore but that deserves serious attention: the inadequacy of CDC-recommended measures to remove SARS-CoV-2 from interior air.
Marin, California, a suburb of San Francisco, is the 14th richest county in the nation. Some 75% of its residents are fully vaccinated – the highest rate in the state and one of the highest in the country.
The unnamed, unvaccinated teacher was reading aloud to students and “reportedly unmasked” even though the school required it. The teacher also “became symptomatic on May 19 with nasal congestion and fatigue” but continued working through May 21. The students, it appears, were masked, and parents of those infected “suggested that students’ adherence to masking and distancing guidelines in line with CDC recommendations was high in class.” Desks were all spaced six feet apart.
Between May 23 and 26, all but two of the 24 students were tested for COVID, and 12 of them came up positive – a 55% rate. Eight of the 12 were symptomatic, including four of the five students in the first row (the fifth tested positive as well). In the second row, three of four students tested received positive results, as did two of four in the fifth row, despite being 30 feet away from the teacher. The case provides a powerful example of how the SARS-CoV-2 virus can linger in the air, drifting far from its original source.
In another classroom, separated from the first by a large outdoor courtyard, 14 students were tested, and six received positive results. Several students in other grades, siblings of those in the original classroom, were later found to be infected, as were four parents (only one of whom was unvaccinated). In all, there were 27 cases, all apparently stemming from the index case involving the teacher.
The rapid spread of the virus throughout the classroom occurred before the Delta variant, which is twice as contagious as previous variants, became established as dominant in the United States. In late May, Delta (B.1.617.2) accounted for only about 5% of cases.
But how exactly did the spread occur in the teacher’s classroom? Below is a diagram from the MMWR report:
In the school, the report notes, “All classrooms had portable high-efficiency particulate air filters and doors and windows were left open.” In fact, as you can see from the diagram, the room was receiving a good deal of cross-ventilation. Ventilation plus high-efficiency particulate air (HEPA) filters is what the Centers for Disease Control and Prevention (CDC) recommends for interior spaces.
A single case is not dispositive, of course, but the CDC should take careful note of the Marin County experience, and a reconsideration of its advice may be in order. The CDC says it bases its recommendations on guidance from ASHRAE, the American Society of Heating, Refrigeration, and Air-Conditioning Engineers, a trade group dominated by the HVAC industry.
The question that CDC, other government agencies, and facilities managers should explore is whether ventilation (either via open windows or HVAC systems) combined with a passive filtration system like HEPA is the best means of mitigating indoor pathogens like SARS-CoV-2. The Marin experience shows that it is not.
The CDC recommends a “layered approach,” and that is certainly correct. Ventilation is necessary but not sufficient. Filters, on the other hand, present problems, the main one being that they are passive. They sit there waiting for pathogens to come to them. But not all pathogens do. Some continue to float in the air, and ventilation, as we saw in Marin, blow them all over an enclosed space. It’s almost certain that some pathogens won’t flow to where the HEPA unit is placed (in this case at the front of the room). In the back two rows, at a minimum of 24 feet away from the teacher, 37.5% of students tested positive.
The alternative to passive filtration is active antiviral elimination – that is, a system that sends particles throughout a space at high speed to deactivate pathogens chemically. Some of these systems also have deficiencies, including production of toxic byproducts like formaldehyde as well as ozone. More advanced versions, including one called Advanced Photocatalysis, developed by the Dallas firm ActivePure, create more efficient reactions, reducing rather than creating byproducts. In trials involving rooms that were already equipped with filter systems, Advanced Photocatalysis was found to reduce the level of pathogens by more than 50%.
CDC is correct to advocate a layered response to COVID, but each of those layers needs to work with maximum effectiveness. Yes, the teacher should have been vaccinated, but it is clear that a large segment of the U.S. population will never be vaccinated. Yes, the teacher should have been wearing a mask, but all of the students evidently were and masking every minute of a workday or school day is nearly impossible. Yes, the teacher should have reported a possible infection right away, but as we enter the cold and flu season, not every runny nose equals COVID. Yes, ventilation is necessary, but large banks of windows were open on a California spring.
The layered element that needs addressing is one that supplements ventilation. In the case of Marin, mitigation was passive and demonstrably ineffective. Mitigation, it seems logical to conclude, needs to be active: seek and deactivate. The CDC and everyone concerned about limiting the damage of COVID would do well to look beyond HVAC industry guidance, as school systems in Philadelphia and throughout the country are currently doing.
COVID Solutions Bulletin
Our mission is to educate people on innovative solutions to the COVID-19 crisis in America. We need to get back to work, to school, to play – to enjoying life. We can’t get there without thwarting the current pandemic and preparing for the possibility of other pathogens to come.
COVID Solutions Bulletin is a publication providing regular updates on new and existing technologies that can help stop the spread of COVID-19, and help clear the air to open America back up.