United States CDC recommends double masking

Across many parts of the country, life in masks has become the norm for the better part of the past year. Now, the United States Centers for Disease Control and Prevention (CDC) is offering new guidance. Yesterday the agency recommended that Americans wear a tighter fitting mask—or even two masks—in order to slow the spread of covid-19. The guidance came with a study that demonstrated that improved masking can reduce exposure to potentially infectious aerosols (this was a study done in a simulated environment using mannequin-like constructs, known as "headforms.")

The particular instructions specify that masks should fit tightly over the nose, mouth, and chin with a wire at the top to prevent air from leaking out along the top; the masks should contain at least two layers. If one only has access to loose-fitting surgical masks, the alternative of placing a tightly fitting cloth mask over the surgical one is suggested. The general idea is to reduce the ability of particles to escape around the edges of the mask. The new guidance goes so far as to recommend modifying medical procedure masks by knotting the ear loops and tucking in any extra material (see the link above for images). Indeed, in the aforementioned experiment, when both the source and receiver "headforms" wore masks modified to fit more tightly, the receiver's exposure to projected particles (simulating a cough) were reduced by more than 95 percent as compared to no masks at all. 

"The bottom line is this: masks work and they work best when they have a good fit and are worn correctly," said CDC Director Dr. Rochelle Walensky in a White House briefing on Wednesday. John T. Brooks, chief medical officer for the CDC's covid-19 response, added that with the circulation of three new variants, "whatever we can do to improve the fit of a mask to make it work better, the faster we can end this pandemic." 

As the death toll in the U.S. approaches 500,000 and as the nation rushes to vaccinate a larger swath of the population, the updated guidance emphasizes mask-wearing as one of the best defenses against more transmissible variants of the SARS-CoV-2 virus. 11 February 2021.

CDC says vaccinations mean quarantine not necessary for all, with caveats galore and incomplete evidence to back it up

The United States Centers for Disease Control and Prevention has issued new guidance stating that the people who are fully vaccinated and are within 3 months of the last dose need not quarantine if they have had exposure to a person with suspected or confirmed covid-19, provided they have been asymptomatic since the exposure. The policy applies to both vaccines currently in use in the United States, as well as those authorized elsewhere (including one-dose regimens).

Evidence to support this is a bit lacking, as we do not know whether vaccinated people can acquire asymptomatic infection and transmit it to others who in turn could become gravely ill. However, there is mounting evidence that at least some spread will be inhibited by the vaccines, as we have covered in Brief19, although the extent and timing of this vaccine benefit remains unknown.

To that end, the CDC guidance acknowledges that the evidence behind this policy is not ironclad. They overtly state that what is behind this policy is the notion that there are "societal benefits of avoiding unnecessary quarantine which may outweigh the potential but unknown risk of transmission, and facilitate the direction of public health resources to persons at highest risk for transmitting SARS-CoV-2 to others." In addition to that, the guidance slips in a fairly controversial statement regarding contagion, saying that "symptomatic and pre-symptomatic transmission is thought to have a greater role in transmission than purely asymptomatic transmission." While this may be true, it's unclear how a person would know that they are presymptomatic as opposed to merely asymptomatic. In sum, the policy seems to be suggesting that this approach could lead to some spread, but that taking this approach might on balance draw attention and resources to people most likely to spread the virus. 11 February 2021.

Changes at the CDC to revitalize reputation

Hitting the ground running on her first day leading the US Centers for Disease Control and Prevention (CDC), Dr. Rochelle Walenksy sat down with JAMA to discuss her priorities in changing the direction of the organization. Amidst a laundry list of plans, three main initiatives stand out.

Public health: part of President Biden's proposed stimulus plan includes a moratorium on private home evictions; until the bill is passed, though, the CDC has issued an extension of a previous agency order effectively banning evictions until March 31 (Previously, Congress was unable to agree on a version of a stimulus package that included the continuation of a similar moratorium). The agency has also pledged a deeper commitment to investing in healthcare infrastructure, a need made more pressing in part due to the overburdening of facilities stemming from a lack of equipment and providers.

Vaccines: To reach a goal of 100 million vaccines in the first 100 days of the Biden administration, the public's access to the vaccine needs to be increased by expanding the vaccinator corps to include military medical providers, public health service corps, medical students, nursing students and other qualified innoculators. The developing of mobile vaccination units, federal vaccination centers, federally-qualified health centers, and pharmacies will provide the doses. In cases in which supply outpaces demand, broadening patient eligibility in order to limit wasted supplies should be considered.

Agency Esteem: The CDC has recently fallen victim to politicization. Over the last year, interference from Washington meant that some evidence-based policies recommended by professionals at the CDC were suppressed, a practice that President Biden vowed would cease on his watch. Dr. Walensky emphasized a commitment to improving the internal morale of the organization and assure the career professionals that they will be able to conduct their work unimpeded. Externally, she wants the CDC to communicate with the American people in lay terms, with communications led by subject-matter experts.

For the CDC to reclaim its prior stature, much work remains. But there seems to be support from the Oval Office down through agency leadership. However, not even this administration, with its pro-science posture, is immune to political winds. Last week, White House Press Secretary Jen Psaki said that Dr. Walensky was speaking in her "personal capacity" when discussing evidence published by the CDC pointing towards the fact that in many circumstances, re-opening schools has not been associated with increased spread of the coronavirus. This statement, while true, was interpreted by some as a declaration that all schools should re-open, a stance with which many teachers' unions would take issue. So while the new administration has said it won't interfere with the CDC's policies, it has already found at least one point of friction in applying that policy. Various. 9 February 2021.

New Emergency Use Authorization for covid-19 therapeutics

On Tuesday the US Food and Drug Administration (FDA) announced an Emergency Use Authorization (EUA) for Eli Lilly's antibodies bamlanivimab and etesivimab as a therapeutic for the treatment of mild to moderate covid-19 patients who are at least twelve years old and at-risk for progression to severe disease or hospitalization. Specifically, this EUA allows for the concomitant administration of bamlanivimab and etesivimab or bamlanivimab alone; excluded are hospitalized patients, those requiring new supplemental oxygen, or an increase in a person's baseline oxygen requirement.

The EUA is based on the Phase 3 results of the BLAZE-1 Trial, which showed a seventy percent reduction in hospitalization and death for the target population, although it should be noted that the investigators changed the primary outcome of interest a few times during the trial, which indicates some degree of cherry-picking. Various. 12 February 2021.

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