COVID-19 Scan for Nov 24, 2021

COVID vaccine correlates of protection
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COVID-19 and healthcare avoidance
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Less death in COVID cancer patients

SARS-CoV-2 antibody levels predict COVID vaccine efficacy, study finds

SARS-CoV-2 antibody concentrations predict COVID-19 vaccine effectiveness, with higher levels correlating with greater protection, according to an ongoing US phase 3 clinical trial yesterday in Science.

A team led by researchers from Fred Hutchinson Cancer Research Center in Seattle evaluated 30,420 adult recipients of the Moderna mRNA COVID-19 vaccine at 99 centers for neutralizing and binding antibodies as correlates of risk for, and protection against, infection.

They measured the antibodies at the second vaccine dose and then again 4 weeks later. Concentrations were inversely associated with COVID-19 infection risk and directly tied to vaccine efficacy.

Vaccine effectiveness in vaccinees with 50% neutralizing antibody levels of 10, 100, and 1,000 international units per milliliter was 78% (95% confidence interval [CI], 54 to 89%), 91% (95% CI, 87% to 94%), and 96% (95% CI, 94% to 98%), respectively.

Based on antibody levels, the estimated risk of SARS-CoV-2 infection was roughly 10 times lower for vaccinees whose antibody concentrations were in the top 10% of values, relative to those with negative or undetectable values.

The results help define immune marker correlates of protection, or biomarkers to measure how much immunity is needed to prevent COVID-19 infection, the study authors said. Identifying and validating a correlate of protection would expedite vaccine research and regulatory approval for existing vaccines for new groups of people, modifications of vaccine regimens, and new vaccines, they added.

"Our findings that all evaluated binding and neutralizing antibody markers strongly inversely correlated with COVID-19 risk, and directly correlated with vaccine efficacy, adds evidence toward establishing an immune marker surrogate endpoint for mRNA COVID-19 vaccines," the researchers wrote.
Nov 23 Science study

 

Study: 1 in 5 people avoided healthcare during initial COVID-19 lockdown

A study yesterday in PLOS Medicine shows that up to 20% of people polled in the Netherlands avoided seeking healthcare during the initial months of the COVID-19 pandemic, even for serious health concerns.

The study is based on results from 5,656 participants of the Rotterdam Study, who answered questions on healthcare from April 2020 to July 2020. The study is an ongoing effort to assess chronic diseases in mid to late life.

One in five participants (20.2%) reported avoiding healthcare during the pandemic. Of those, 36.3% reported symptoms that warranted urgent care, including limb weakness (13.6%), heart palpitations (10.8%) and chest pain (10.2%). Adjusted odds ratios showed women were more likely to avoid care (1.58; 95% confidence interval [CI], 1.38 to 1.82), as were those with poor self-appreciated health (per-level decrease, 2.00; 95% CI, 1.80 to 2.22).

High rates of depression were also related to avoiding healthcare.

In a PLOS press release, senior author Silvan Licher said, "One in five avoided healthcare during COVID-19 lockdown, often with alarming symptoms like chest pain or limb weakness. Vulnerable citizens were mainly affected, emphasising the urgent need for targeted public education." 
Nov 23 PLOS Medicine
study
Nov 23 PLOS press
release 

 

Significant improvement noted in death rates of COVID-19 cancer patients

Research published today in JAMA Oncology finds lower estimated all-cause death rates among COVID-19–infected European cancer patients over time.

The study, by the OnCovid Study Group in Europe used data from a registry of adults with blood cancer or solid tumors diagnosed as having COVID-19 from 35 centers in six countries (Belgium, France, Germany, Italy, Spain, and the United Kingdom) from Feb 27, 2020, to Feb 14, 2021, before the emergence of the Delta (B1617.2) variant. Patients were, on average, 68 years old, and 52.8% were men.

The authors noted a significant time-dependent improvement in 14-day case-fatality rates, from 29.8% in February to March 2020, to 20.3% in April to June 2020, 12.5% in July to September 2020, 17.2% in October to December 2020, and 14.5% in January to February 2021.

In the first major European outbreak (February to June 2020), the 14-day case-fatality rate was 25.6%, compared with 16.2% in the second outbreak (July 2020 to February 2021). After adjustment for multiple factors, patients diagnosed as having COVID-19 in the first outbreak were at higher risk of death by 14 days (hazard ratio [HR], 1.85) and 3 months (HR, 1.28) than those diagnosed in the second outbreak.

The study authors said that the lower death rate over time may be linked to earlier COVID-19 diagnosis, better treatments, and changes in community SARS-CoV-2 transmission.

While the authors acknowledged the difficulty of direct measurement of the factors that may have contributed to the lower death rate among patients with cancer and COVID-19, they conclude, "This case series provides an important contemporary portrait of the evolving outcomes of COVID-19 in patients with cancer, highlighting the importance of widespread SARS-CoV-2 testing as a strategy to facilitate early diagnosis of COVID-19 and maintain the appropriate therapeutic pathway for patients with cancer despite the ongoing threat of an unresolved global pandemic."
Nov 24 JAMA Oncol study

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