COVID-19 Scan for Nov 10, 2022

News brief

Vaccination produces higher cord blood antibodies than COVID infection

JAMA Network Open published a new study yesterday showing higher cord blood COVID-19 antibodies in women who were vaccinated compared with those who were infected with COVID-19, suggesting vaccination produces more than 10-fold higher antibody concentrations in unborn babies compared to natural infections.

The study was based on patients who gave birth at Pennsylvania Hospital in Philadelphia between Aug 9, 2020, and Apr 25, 2021, a period encompassing when initial mRNA vaccine series became available, but before the approval of booster doses. In total, 585 pregnancies with cord blood serum samples were identified, including 169 patients who had been vaccinated but never infected and 408 who had been infected but not vaccinated.

The researchers also detected IgG antibodies to SARS-CoV-2 in the cord blood from more than 95% of newborns (557 of 585) in the study.

Those with maternal vaccination only had significantly higher antibody levels compared to the infection group, but transfer ratios, or how much the antibody levels in the cord blood match the antibody levels in the mother, were lower in the vaccinated group compared with the natural infection group, (0.80 [95% confidence interval CI, 0.68-0.93] vs 1.06 [95% CI, 0.98-1.14]; P < .001).

The authors said time to transfer was most affected by time since vaccination, with 8 weeks or more between vaccination and delivery producing the highest levels.

"These findings can inform optimal COVID-19 vaccination strategy during pregnancy," said senior author Karen M. Puopolo MD, PhD, of the Children's Hospital of Philadelphia and Chief of the Section on Newborn Medicine at Pennsylvania Hospital in a press release. "Patients should plan to get vaccinated with ample time before their due date, so that they – and their babies – can benefit from a robust immune response."
Nov 9 JAMA Netw Open study
Nov 9 Children's Hospital of Philadelphia press release


Israeli study shows fourth Pfizer dose protection wanes by 6 months

Yesterday in a letter to the New England Journal of Medicine, Israeli researchers reported an overall vaccine effectiveness of a fourth Pfizer COVID vaccine dose of 41% in the first 6 months, but they said protection decreased from 52% during the first 5 weeks after vaccination to no protection at 15 to 26 weeks.

The findings come from an ongoing prospective cohort study of healthcare workers vaccinated in Israel. Vaccine effectiveness was determined by comparing infection rates following the fourth dose (days 7 through 35, days 36 through 102, or days 103 through 181 after receipt of the fourth dose) to infections in those who received a third dose only, at least 4 months earlier.

"Antibody response peaked at approximately 4 weeks, waned to levels seen before the fourth dose by 13 weeks, and stabilized thereafter," the authors said.

The protection offered by a fourth dose was not as robust as the protection offered by a third dose, the authors said, with no substantial additional effectiveness over a third dose at 15 to 26 weeks after vaccination.

"These results suggest that the fourth dose, and possibly future boosters, should be timed wisely to coincide with disease waves or to be available seasonally, similar to the influenza vaccine. Whether multivalent booster doses will result in longer durability remains to be seen," the authors concluded.
Nov 9 N Engl J Med study

News Scan for Nov 10, 2022

News brief

Unneeded antibiotics for respiratory infections tied to harm, higher costs

A study of more than 3 million patients with bacterial and viral respiratory infections found that inappropriate antibiotic prescriptions were associated with increased risk of adverse events and higher healthcare costs, researchers reported today in Clinical Infectious Diseases.

The study, conducted by researchers with the Washington University School of Medicine in St. Louis and the Pew Charitable Trusts, used data from the MarketScan Commercial Database to analyze antibiotic exposure among adults aged 18 to 64 years who were diagnosed as having a bacterial or viral infection from April 2016 through September 2018.

They analyzed inappropriate versus appropriate prescriptions, focusing on the relationship between inappropriate antibiotics and adverse drug events and 30-day attributable expenditures. Inappropriate antibiotics were defined as non–guideline-recommended antibiotics for bacterial infections and any antibiotic for viral infections.

Among 3,294,598 eligible adults (median age, 43 years; 41% male), there were 1,656,960 bacterial respiratory infections and 1,637,638 viral respiratory infections. The proportion of adults with bacterial infections who received inappropriate antibiotics differed by infection, ranging from 43% (sinusitis) to 56% (pharyngitis), while inappropriate antibiotics for viral infections ranged from 7% (influenza) to 66% (bronchitis).

Analysis of different infections found that inappropriate antibiotics for pharyngitis were associated with an increased risk of Clostridioides difficile infection (hazard ratio [HR], 2.90; 95% confidence interval [CI], 1.31 to 6.40) and nausea/vomiting/abdominal pain (HR, 1.10; 95% CI, 1.03 to 1.08), while an increased of vulvovaginal candidiasis was linked to inappropriate antibiotics for viral upper respiratory infections (HR, 1.24; 95% CI, 1.14 to 1.34 ) and non-suppurative otitis media (ear infection; HR, 1.39; 95% CI, 1.09 to 1.77).

The mean 30-day total attributable expenditure for inappropriate antibiotics for bacterial infections ranged from $18 (sinusitis) to $67 (pharyngitis) and from –$53 (bronchitis) to $49 (influenza) for viral infections.

"These results support the need for increased outpatient antibiotic stewardship efforts to discourage antibiotic prescribing for viral infections, encourage appropriate selection of guideline-recommended antibiotics for bacterial infections, and reduce antibiotic-related harms and expenditures," the study authors concluded.
Nov 9 Clin Infect Dis abstract


Listeria outbreak tied to deli products sickens 16 in 6 states, 1 fatally

The Centers for Disease Control and Prevention (CDC) yesterday announced a Listeria monocytogenes outbreak linked to meat and cheese sold at delis that has so far sickened at least 16 people, one of them fatally, in 6 states.

So far, officials haven't identified a specific food source, which they said is difficult, given that Listeria spreads easily from food to surfaces in the deli environment and can persist in display cases and on equipment.

Interviews with 12 sick people revealed that 11 had eaten meat and cheese from delis. Of seven sick people in New York, five had bought meat or cheese from at least one location of NetCost Market, a grocery chain that sells international foods. However, the CDC said it doesn't think NetCost Market is the source of the outbreak, because some sick people did not shop there. "A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states," the CDC said.

In 2021, New York state and city officials found the outbreak strain in environmental and food samples from the same NetCost Market store in Brooklyn and in food from one of the stores on Staten Island. After deep cleaning and negative testing, Listeria was found again at the Brooklyn store in September 2022.

Illness onsets range from April 2021 to Sep 29, 2022. Affected states include New York (7), Maryland (3), Illinois (2), Massachusetts (2), California (1), and New Jersey (1). All of the sick people are adults, and of 13 people with ethnicity information, 11 are of Eastern European descent. Thirteen people were hospitalized, including a Maryland resident who died. One of the sick people was a pregnant woman who lost her baby.

The CDC has advised people at higher risk of Listeria illness—pregnant women, older people, and those with weakened immune systems—to avoid eating meat and cheese from deli counters unless it is heated to at least 165°F.
Nov 9 CDC outbreak notice


Avian flu outbreaks strike more poultry flocks in 8 states

Over the past few days, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has reported highly pathogenic avian influenza outbreaks in eight states, including three with outbreaks at commercial farms.

The new developments brought the number of birds lost in the current Eurasian H5N1 outbreaks within a stone's throw of the record 50.5 million-bird loss that producers sustained during avian influenza outbreaks in 2015. The latest outbreaks have now led to the loss of 50.3 million birds across 46 states, according to APHIS.

Pennsylvania has reported three outbreaks at turkey farms, all in Lehigh County, which together have more than 46,000 birds. Iowa reported its second recent outbreak at a layer farm in Wright County, which has more than 1 million birds. Iowa has been the hardest-hit state regarding poultry losses. In Wisconsin, the virus struck a gamebird farm in Jefferson County that houses 180,000 birds.

Seven states reported more outbreaks in backyard birds, including Iowa, Pennsylvania, Washington, Ohio, Virginia, Wyoming, and New York.
USDA APHIS avian influenza updates

In international developments, France's agriculture ministry raised its avian flu alert, which triggered a requirement that farmers must keep poultry indoors, according to Reuters.

The pace of outbreaks has risen over the past few months, with France experiencing its worst outbreaks leading to the culling of 22 million birds so far. The United Kingdom recently announced a similar requirement to protect poultry.
Nov 10 Reuters story

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