COVID-19 Scan for Sep 08, 2021

High COVID vaccine protection
CPAP therapy for COVID-19

COVID mRNA vaccine effectiveness high in those 16 and up

The Pfizer/BioNTech and Moderna mRNA-based COVID-19 vaccines have a collective 91% vaccine efficacy against SARS-CoV-2 infection in Americans 16 years and older, according to a test-negative study published in the Journal of Infectious Diseases today.

The researchers looked at 812 people who were seeking outpatient medical care for potential COVID-19 infection. About 29% (236) tested positive, of whom 8.5% were partially vaccinated and 7.2% were fully vaccinated. Of the remaining people who received negative COVID-19 tests, 29% were partially vaccinated and 71% were fully vaccinated.

Vaccine effectiveness was calculated to be 91% for those fully vaccinated and 75% for those who were partially vaccinated (95% confidence intervals, 83% to 95% and 55% to 87%, respectively).

The cohort was enrolled from five study sites in Michigan, Pennsylvania, Texas, Washington, and Wisconsin. Participation began for those 65 years and older on Feb 1 and for those 16 to 64 years on Mar 22 due to vaccine prioritization plans, with both groups closing May 28. At this time, the Alpha (B117) variant was identified in 56% of 36 sequenced samples.

"With the high vaccine effectiveness against mild to moderate COVID-19 observed during the study period, early community vaccination strategies likely had a marked impact on disease burden," the researchers conclude.
Sep 8 J Infect Dis abstract


CPAP may be ineffective for severe COVID-19, study says

Continuous positive airway pressure therapy (CPAP), which is used for respiratory failure, may not benefit COVID-19 patients with severe disease who are not likely to benefit from invasive mechanical ventilation (nIMV), according to a study today in EClinicalMedicine. The researchers say CPAP is often used outside intensive therapy and high-dependency units.

The researchers pooled data from nIMV patients in seven hospitals in the North West of England during the United Kingdom's first and second pandemic waves (Mar 1 to May 31, 2020, and Sep 1 to Dec 31, 2020).

Among 479 patients who either received CPAP (233) or oxygen therapy (246), 30-day mortality did not show significant difference (77.7% in CPAP group vs 75.6% in oxygen group). Thirty-day mortality for the CPAP group had an adjusted odds ratio (aOR) of 0.84 compared with the oxygen group (95% confidence interval, 0.57 to 1.23, p = 0.37).

Higher 30-day mortality rate was, however, crudely associated with advancing age (OR, 1.56 per 10-year increase in age), increasing urea (OR, 2.44 per 10 millimoles per liter increase), and lower SpO2 (peripheral capillary oxygen saturation; OR, 0.68 per 5% SpO2 increase). Obese patients had significantly lower mortality rates (OR, 0.55).

While 48.9% of CPAP recipients discontinued the therapy, the researchers say the reasonable duration of use and further sensitivity analyses indicated that those patients did not significantly affect the results.

"Given the resources required to provide CPAP it raises the question as to whether it should be provided to patients who are nIMV, which has been commonplace during the COVID-19 pandemic. Importantly, however, we found no evidence of worsened outcomes in patients treated with CPAP," the researchers write.

The complete cohort was 64% male, with an average of 77 years. People in the oxygen group were slightly older (78 vs 77 years) and had a higher rate of cardiovascular disease (76% vs 64%).
Sep 8 EClinicalMedicine

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