COVID-19 Scan for Dec 03, 2021

Health worker COVID-19 risk factors
COVID vaccine in cancer patients

COVID-19 risk factors in healthcare workers spelled out

Close contact with COVID-19 cases outside of work is the biggest risk factor for infections among American healthcare workers, according to research published yesterday in Emerging Infectious Diseases.

The case-control study was based on participants from 25 healthcare facilities across the country and included 33,644 healthcare workers (3,416 cases and 30,228 controls) who reported COVID-19 infections and exposures to Emerging Infections Program (EIP) sites. Among 3,416 COVID-19 cases, 1,172 healthcare personnel were interviewed.

The biggest risk factor for COVID-19 infection was reported close contact with persons with COVID-19 outside the workplace (described by 36.8% of workers), while 32.8% reported close contact with COVID-19 patients in the workplace in the 14 days before illness onset.

"Approximately two thirds of cases and controls reported close contact with family members with COVID-19," the authors wrote. "Higher percentages of cases than controls identified themselves as being Hispanic or Latino, being <30 years of age, being administrative personnel, and having close contact with persons with COVID-19 outside the workplace."

When compared to matched controls, odds for cases were 6.2-fold higher for reporting close contact with persons with COVID-19 outside the workplace, the authors said. The odds were 1.6-fold higher for reporting close contact with COVID-19 patients in the workplace.
Dec 2 Emerg Infect Dis study


COVID vaccine affords cancer patients good protection against infection

A US Veterans Affairs (VA) study finds that the COVID-19 vaccine offered good protection against infection starting 2 weeks after the second dose in cancer patients, who are at increased risk for severe COVID-19.

The retrospective nationwide study, published yesterday in JAMA Oncology, involved 29,152 vaccinated patients who received systemic cancer therapy at VA sites from Aug 15, 2010, to May 4, 2021.

Each day from Dec 15, 2020, to May 4, 2021, newly vaccinated patients were matched in a 1:1 ratio with unvaccinated controls. A proxy for vaccine effectiveness was defined as 1 minus the risk ratio for COVID-19 infection in vaccinated patients versus controls. Median patient age was 74.1 years, 95% were men, and 71% were White.

Estimated vaccine effectiveness was 58% (95% confidence interval [CI], 39% to 72%) starting 14 days after the second dose in patients who received systemic cancer therapy in the previous 6 months.

Effectiveness rose to 85% (95% CI, 29% to 100%) in patients who had not received systemic treatment in the previous 6 months and was 76% (95% CI, 50% to 91%) among those receiving hormone therapy. Estimated vaccine effectiveness in patients who received chemotherapy in the 3 months before the first dose was 57% (95% CI, –23% to 90%) starting 14 days after the second dose.

During a median follow-up of 47 days, 161 vaccinated patients (0.55%) tested positive for COVID-19, compared with 275 controls (0.94%). Seventeen vaccinated patients died of their infections, versus 27 controls.

"In this cohort study, COVID-19 vaccination was associated with lower SARS-CoV-2 infection rates in patients with cancer," the study authors wrote. "Some immunosuppressed subgroups may remain at early risk for COVID-19 despite vaccination, and consideration should be given to additional risk reduction strategies, such as serologic testing for vaccine response and a third vaccine dose to optimize outcomes."

The researchers called for studies in different patient groups with longer follow-up and research to determine the optimal vaccination regimen based on cancer and treatment type.
Dec 2 JAMA Oncol study

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