Sign our Expert Letter to Mandy Cohen: Tell the CDC we need science-based isolation guidelines

CDC must stop caving to corporate pressure and follow the science and protect our health.

It’s been over a month since the CDC released new, irresponsible guidelines on COVID isolation which are not substantiated by scientific evidence. Our fight to take public health out of the hands of corporate interests and protect our collective well being continues.

The CDC’s reduced COVID isolation policy will make workplaces less safe by giving employers justification to deny workers the time necessary to heal and recover. It will make public spaces even less accessible to disabled and immunocompromised people, seniors and others who would like to avoid contracting preventable illnesses at their workplaces, schools, healthcare centers and other public spaces.

As part of our strategy to push back, we’ve drafted an expert letter to CDC Director Mandy Cohen telling her to reinstate science-based COVID isolation guidelines. Reviewing the wide body of evidence on COVID’s infectiousness, the letter highlights the fact that fever is not a reliable indicator of COVID transmissibility and that many infections continue to be asymptomatic. We urge the CDC to consider the highly variable length of infectiousness in their recommendations and to adopt a test-based approach for ending isolation.

This letter is for public health professionals, scientists, healthcare workers, disability advocates, and others who consider themselves experts in public health.

Please read the letter below and add your name. Join us by spreading the news widely in your communities.

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Mandy Cohen, MD, MPH, Director

Centers for Disease Control and Prevention

1600 Clifton Road

Atlanta, Georgia 30329

Dear Dr. Cohen:

As medical professionals, public health professionals, scientists, and public health advocates, we call on you to fulfill your duty as the Director of the Centers for Disease Control and Prevention (CDC) to protect the health and safety of the people by reinstating science-based COVID isolation guidelines with a minimum isolation period of 7 to 10 days. Under the guise of a “simplified” approach, the new isolation guidance,¹ published on 3/1/2024, endangers public health by drastically reducing, and in some situations eliminating, COVID isolation. 

The CDC’s 3/1/2024 updated COVID isolation guidance is inappropriate for the following reasons:

1. The infectious period for COVID routinely extends beyond the recommended isolation period.

The CDC’s updated isolation guidelines do not capture the typical length of the infectious period for COVID, which is expected to last around 7 to 10 days, with variability among individuals and viral variants.² In a study conducted in 2022-2023, the peak median viral load was around day 4 to 5 of symptoms.³ This finding runs counter to the following statement from the CDC’s own background for the updated guidance: “This recommendation addresses the period of greatest infectiousness and highest viral load for most people, which is typically in the first few days of illness and when symptoms, including fever, are worst.”⁴ An appropriate isolation approach should extend long enough to capture the infectious period for most people and should incorporate a test-based approach for exit from isolation.

The updated isolation guidance places a scientifically unfounded emphasis on fever and other symptoms, which are often absent in COVID patients and are not required for disease transmission. Asymptomatic and presymptomatic infections,^5,6 identified through contact tracing and testing, warrant appropriate isolation to prevent transmission. The CDC’s cited references and the broader scientific literature do not support relying on fever and on subjective improvement in symptoms as key indicators of infectiousness. The CDC has a responsibility to formulate policy decisions based on appropriate evidence applied using a precautionary approach. The CDC also has the capability to generate the evidence if it does not exist or is insufficient.  

The updated isolation guidance will be used by employers to justify forcing people back to work while they are still contagious and still recovering from their COVID infection.⁷ The public needs support from the CDC to bolster worker access to and use of paid sick time. The updated guidance makes workplaces, schools, and other public spaces riskier for all people and inaccessible for those who must avoid COVID infection, especially those at high risk of severe COVID,⁸ those with high risk family members, and members of disproportionately impacted and marginalized communities.⁹

2. COVID continues to be a serious threat to health, through both acute infections and Long COVID.

In 2023 alone, COVID killed over 75,000 people in the US.¹⁰ We continued to see over 1,000 weekly COVID deaths as of February 10, 2024.¹⁰ The risk of Long COVID is about 10% following a single infection.¹¹ As of March 4, 2024, the Census Bureau found 17.6% of US adults reported ever having experienced Long COVID (almost 35 million people¹²), and 6.7% of US adults are currently experiencing Long COVID.¹³ COVID is known to commonly cause long-term sequelae across a broad range of organ systems, with repeated infections worsening the effects.¹⁴ Vaccination and antiviral treatment are underutilized (see below) and only provide partial protection from Long COVID.^11,15 We still lack specific treatments for Long COVID. Due to the ongoing serious risks from both acute infection and Long COVID, preventing new COVID infections through appropriate isolation should be a priority.

3. Vaccination and antivirals for COVID are underutilized and do not provide complete protection from serious disease.

While vaccination and prompt antiviral treatment can reduce the risk of severe COVID, neither provides complete protection, and both are underutilized. As of February 24, 2024, only 22.2% of US adults¹⁶ and 13.1% of children¹⁷¹⁷ have received the 2023-2024 COVID vaccines. 

Although rates of multisystem inflammatory syndrome in children (MIS-C) have slowed since 2020-2021, 112 cases were reported in 2023, with 82.1% of those occurring in unvaccinated children. Among cases in vaccinated children, 60% occurred in children who had not received a booster within the last year.¹⁸ The updated guidance will cause more children to be exposed to the virus, particularly in daycare and school settings. 

There are significant ongoing barriers to antiviral access for populations at high risk of severe COVID. In a 2023 study, only 31.9% of eligible patients with risk factors for severe COVID were prescribed COVID antiviral therapy.¹⁹ In April of this year, one established mechanism for access to timely no-cost testing and treatment with Paxlovid, the NIH-funded “Home Test to Treat” program, will be ending.

Rebound infections with or without symptoms²⁰ following antiviral treatment must also be addressed with appropriately precautionary and science-based guidelines. In patients who have been treated for COVID using antivirals, appropriate isolation with a test-based approach to exit from isolation is especially important to reduce the population risk of emergence and spread of treatment-resistant variants.

4. COVID spreads year-round, unlike influenza and RSV.

Unification of COVID guidance with influenza and other respiratory viruses is inappropriate from an epidemiologic standpoint, as COVID spread continues to occur year-round. Peaks in COVID wastewater and hospitalizations have often occurred in fall-winter but also occur in other seasons (such as April 2021 and July 2022). In a striking contrast to influenza and RSV, there is no season where a near-zero level of COVID wastewater levels or hospitalizations can be observed. The lowest level of weekly COVID hospitalizations within the last year was 6,324 the week of June 24, 2023.²¹

The CDC has recognized this ongoing year-round risk of COVID in its recommendation from the Advisory Committee on Immunization Practices that all people aged 65 and older receive another 2023-2024 COVID booster this spring.²² Unified guidance for viruses with differing patterns of spread creates confusion over when to use and how to implement the guidance. Clear, virus-specific guidance is needed for public health professionals, healthcare workers, and community members to understand that they should utilize COVID testing in conjunction with COVID-specific isolation year-round, including outside of the typical fall-winter respiratory viral season.

5. COVID is a systemic disease with harmful impacts (acute infections and Long COVID) that are greater than influenza and RSV.

Compared to patients hospitalized for influenza, patients hospitalized for COVID experience a higher risk of death, higher risk of long term consequences, and greater reductions in disability-adjusted life years (DALYs) overall.²³ The incidence rate for COVID also remains higher than influenza and RSV, resulting in a wider effect on the entire population. Considering the impact of acute infections as well as Long COVID, the population level harm is greater for COVID than for RSV and other respiratory viruses.

6. The isolation update was developed and implemented without appropriate public engagement and without input from a broad range of experts.

The process of updating the COVID isolation guidance was conducted without transparency and without public comment. The agency must make public comment conveniently available to all, and especially including disproportionately impacted and marginalized communities.⁹ A broad range of expertise must be incorporated into CDC processes and explicitly used in decision-making to ensure that COVID isolation policies protect people and communities, especially those most vulnerable to an infection and consequently Long COVID. 

Concluding Remarks:

The above points cite much of the same evidence that is used within the CDC’s own background document; however, our demand for science-based COVID isolation guidelines with a minimum isolation period of 7 to 10 days represents a practical application of the precautionary principle. We urge you to engage the public who are in communities directly affected by these policies, and to correct this guidance and recommit to an agenda that protects population health and promotes policies which enable all people to thrive. 

Given the well-established and growing body of evidence of COVID’s harmful and long-lasting impacts, transmission without symptoms, and the duration of infectiousness, we call upon you to correct the agency’s recently announced COVID isolation guidelines and to do so using an open, science and evidence based, precautionary, and consistent approach. Only with a transparent process, meaningful public engagement, and clear prioritization of the public’s health will your agency be able to regain the public’s trust.

Signed,

Kaitlin Sundling, MD, PhD, Pathologist in Wisconsin

Samuel R. Friedman, PhD, Research Professor of Population Health in New York

Shimi Sharief, MD, MPH, Nephrologist and Public Health Physician in Oregon

Zoey Thill, MD, MPP, MPH, Family Medicine Physician in New York

1. Respiratory Virus Guidance. Published March 6, 2024. Accessed March 7, 2024. https://www.cdc.gov/respiratory-viruses/guidance/respiratory-virus-guidance.html ↩︎

2. Puhach O, Meyer B, Eckerle I. SARS-CoV-2 viral load and shedding kinetics. Nat Rev Microbiol. 2023;21(3):147-161. doi:10.1038/s41579-022-00822-w ↩︎

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4. Background for CDC’s Updated Respiratory Virus Guidance | Respiratory Illnesses | CDC. Published March 5, 2024. Accessed March 23, 2024. https://www.cdc.gov/respiratory-viruses/background/index.html ↩︎

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8. Ajufo E, Rao S, Navar AM, Pandey A, Ayers CR, Khera A. U.S. population at increased risk of severe illness from COVID-19. Am J Prev Cardiol. 2021;6:100156. doi:10.1016/j.ajpc.2021.100156 ↩︎

9. Jirmanus L, Valenti R, Schwartzman EG, et al. Too Many Deaths, Too Many Left Behind: A People’s External Review of the U.S. Centers for Disease Control and Prevention’s COVID-19 Pandemic Response. AJPM Focus. Published online February 24, 2024. doi:10.1016/j.focus.2024.100207 ↩︎

10. CDC. Trends in United States COVID-19 Hospitalizations, Deaths, Emergency Department (ED) Visits, and Test Positivity by Geographic Area. Centers for Disease Control and Prevention. Published March 28, 2020. Accessed March 7, 2024. https://covid.cdc.gov/covid-data-tracker/#trends_weeklydeaths_select_00 ↩︎

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15. Razzaghi H, Forrest CB, Hirabayashi K, et al. Vaccine Effectiveness Against Long COVID in Children. Pediatrics. Published online March 8, 2024:e2023064446. doi:10.1542/peds.2023-064446 ↩︎

16. Vaccination Trends—Adults. Published February 14, 2024. Accessed March 7, 2024. https://www.cdc.gov/respiratory-viruses/data-research/dashboard/vaccination-trends-adults.html ↩︎

17. Vaccination Trends—Children. Published February 14, 2024. Accessed March 7, 2024. https://www.cdc.gov/respiratory-viruses/data-research/dashboard/vaccination-trends-children.html ↩︎

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19. Levy ME, Burrows E, Chilunda V, et al. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antiviral Prescribing Gaps Among Nonhospitalized High-Risk Adults. Clinical Infectious Diseases. Published online January 3, 2024:ciad796. doi:10.1093/cid/ciad796 ↩︎

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21. CDC. Trends in United States COVID-19 Hospitalizations, Deaths, Emergency Department (ED) Visits, and Test Positivity by Geographic Area. Centers for Disease Control and Prevention. Published March 28, 2020. Accessed March 23, 2024. https://covid.cdc.gov/covid-data-tracker/#trends_weeklyhospitaladmissions_select_00 ↩︎

22. Older Adults Now Able to Receive Additional Dose of Updated COVID-19 Vaccine. Centers for Disease Control and Prevention. Published March 1, 2024. Accessed March 23, 2024. https://www.cdc.gov/media/releases/2024/s-0228-covid.html ↩︎

23. Xie Y, Choi T, Al-Aly Z. Long-term outcomes following hospital admission for COVID-19 versus seasonal influenza: a cohort study. The Lancet Infectious Diseases. 2023;24(3):239-255. doi:10.1016/S1473-3099(23)00684-9 ↩︎