Observatory and Fast Facts

Oct. 26, 2021
CDC updates infection prevention recommendations

The Centers for Disease Control and Prevention (CDC) has updated its guidance for infection prevention and control during the COVID-19 pandemic.

Specifically, the agency says that fully vaccinated people in counties with low to moderate community transmission do not need to wear respirators or masks while inside healthcare facilities. However, the CDC says the “safest practice” is for everyone to wear a face covering, or what the agency refers to as “source control.”

In addition, fully vaccinated healthcare personnel could choose not to wear source control or physically distance when they are in well-defined areas that are restricted from patient access (e.g., staff meeting rooms or kitchen). However, they should wear source control when they are in areas of the healthcare facility where they could encounter patients (e.g., hospital cafeteria or common halls and corridors).

Source control options for healthcare personnel include:

  • A NIOSH-approved N95 or equivalent or higher-level respirator
  • A respirator approved under standards used in other countries that are similar to NIOSH-approved N95 filtering facepiece respirators (note: these should not be used instead of a NIOSH-approved respirator when respiratory protection is indicated)
  • A well-fitting mask

The agency clarified recommended intervals for testing. Asymptomatic healthcare personnel with a higher-risk exposure and patients in close contact to someone with SARS-CoV-2 infection, regardless of vaccination status, should have a series of two viral tests for SARS-CoV-2 infection. In these situations, testing is recommended immediately (but not earlier than 2 days after the exposure) and, if negative, again 5–7 days after the exposure. However, testing is not recommended for people who have had SARS-CoV-2 infection in the last 90 days if they remain asymptomatic; this is because some people may have detectable virus from their prior infection during this period.

Cognitive impairment is highly likely for severe COVID-19 patients

In a study of nearly 150 patients hospitalized for COVID at the beginning of the pandemic, researchers found that 73% had delirium, a serious disturbance in mental state wherein a patient is confused, agitated and unable to think clearly.

Patients with delirium tended to be sicker, with more comorbidities like hypertension and diabetes, and appeared to have more severe COVID-related illness as well, said study author Phillip Vlisides, MD of the Department of Anesthesiology at Michigan Medicine.

Using patient medical records and telephone surveys following hospital discharge for patients hospitalized in the intensive care unit between March and May 2020, the team attempted to identify common threads amongst patients who developed delirium.

The disease itself can lead to reduced oxygen to the brain as well as the development of blood clots and stroke, resulting in cognitive impairment. In addition, inflammatory markers were greatly increased in patients with delirium. Confusion and agitation could be a result of inflammation of the brain.

Care teams often were unable to perform standard delirium reduction techniques, such as exercises designed to get a patient moving or allowing visitors or objects from home to orient patients while in the hospital.

Furthermore, there was a correlation between the use of sedatives and delirium — patients with delirium were sedated more often and frequently at higher doses. “It is common to use IV sedatives in the ICU, particular for patients on a ventilator. However, from talking to nurses, we found that patients with severe COVID were inherently more delirious and agitated at baseline, perhaps prompting more sedative use.”

The study also found that cognitive impairment can persist even after discharge. Almost a third of patients did not have their delirium marked as resolved in their chart upon leaving the hospital and 40% of these patients required skilled nursing care. Almost a quarter of patients screened positive for delirium based on assessment by their caretaker. For some patients, these symptoms lasted for months. This can make managing the recovery process after hospitalization that much more difficult.

Gut bacteria might be an indicator of colon cancer risk

A study published in the journal Cell Host & Microbe reported that the increased presence of certain bacteria in a gut biome indicates a greater likelihood that colon polyps will become cancerous, according to a news release from the University of Washington.

In his research, William DePaolo, PhD, Associate Professor at the University of Washington School of Medicine, tracked 40 patients who had undergone routine colonoscopies and had biopsies taken near the polyps to identify bacteria present at relatively higher levels compared with those of patients who were polyp-free. All the patients were between the ages 50 and 75, and 60% were women.

“The rising incidence of colorectal cancer is a major health concern, but little is known about the composition and role of microbiota associated with precancerous polyps,” the study states.

DePaolo’s research team found that a common bacteria, non-enterotoxigenic Bacteroides fragilis, was elevated in the mucosal biopsies of patients with polyps.The research also found distinct microbial signatures distinguishing patients with polyps from those without polyps and established a correlation between the amount of B. fragilis in the samples and the inflammation of small polyps.

Upon closer examination, DePaolo found that the B. fragilis from patients with polyps differed in its ability to induce inflammation compared to the B. fragilis from polyp-free individuals.

Also, when people think of the microbiome and its role in disease, they often think of compositional changes where a potentially dangerous bacteria takes over, he added.

“What our data suggests is that, in order to survive within an environment where metabolic and inflammatory changes are occurring, a normally healthy gut and related bacteria may adapt in such a way that causes it to contribute to the inflammation rather than suppress it,” DePaolo explained.

Only 5% of the polyps in the colon actually turn out to be cancerous, he said. He said polyps seem to develop in the same areas of the colon repeatedly — and he theorized that in fact new screenings for colon cancer could look for key bacteria inhabiting the gut — and the amounts of this particular strain of B. fragilis — before pre-cancerous polyps even develop.

The next step, he said, is to expand the study to 200 patients to determine whether a fecal sample might be used as a surrogate for the mucosal biopsy.

Oral antiviral reduced risk of hospitalization, death for COVID-19 patients

Merck and Ridgeback Biotherapeutics announced that the companies’ investigational oral antiviral medicine significantly reduced the risk of hospitalization or death in at-risk, non-hospitalized adult patients with mild-to-moderate COVID-19.

In an interim analysis of a Phase 3 study, the antiviral medication, molnupiravir, reduced the risk of hospitalization or death by approximately 50%. Approximately 7.3% of patients who received molnupiravir were either hospitalized or died through day 29 following randomization (28/385), compared with 14.1% of placebo-treated patients (53/377) through day 29. No deaths were reported in patients who received molnupiravir, as compared to eight deaths in patients who received a placebo.

At the recommendation of an independent data monitoring committee and in consultation with the U.S. Food and Drug Administration (FDA), Merck said the companies stopped recruitment into the study early due to these results.

Merck also said it plans to submit an application for emergency use authorization (EUA) to the U.S. Food and Drug Administration (FDA) as soon as possible based on these findings and plans to submit marketing applications to other regulatory bodies worldwide. If authorized, molnupiravir could be the first oral antiviral medicine for COVID-19, Merck says.