COVID-19 Scan for Mar 17, 2022

News brief

Israeli study points to modest 4-dose vaccine protection against Omicron

Four-dose efficacy of mRNA vaccines against symptomatic Omicron COVID-19 infection is modest, according to a research letter yesterday in the New England Journal of Medicine that described a small study in Israel.

Of 1,050 eligible Israeli healthcare workers, 154 received a fourth dose of Pfizer and 120 received a fourth dose of Moderna. The researchers selected two age-matched controls from the remaining eligible participants for each person vaccinated.

The fourth dose produced a robust immune response and caused no concerning adverse events. Overall, 25.0% of the volunteers in the control group were infected with Omicron, compared with 18.3% in the Pfizer group and 20.7% in the Moderna group.

The researchers reported vaccine efficacy of 30% for Pfizer and 11% for Moderna for any SAR-CoV-2 infection, but neither vaccine achieved statistical significance for this measure. Vaccine protection against symptomatic COVID-19 was 43% for Pfizer and 31% for Moderna. Omicron accounted for 100% of circulating SARS-CoV-2 in Israel at the time of the study.

The authors note, "Our cohort was too small to allow for accurate determination of vaccine efficacy. However, within the wide confidence intervals of our estimates, vaccine efficacy against symptomatic disease was 65% at most."

They conclude, "A fourth vaccination of healthy young health care workers may have only marginal benefits. Older and vulnerable populations were not assessed." Also, they did not assess a fourth dose against severe COVID-19.
Mar 16 N Engl J Med study

Moms spread COVID-19 to newborns less than 2% of time, data show

SARS-CoV-2 is transmitted from mother to baby before, during, and after childbirth about 1.8% of the time, and vaginal births and breastfeeding do not raise the risk, finds a meta-analysis today in BMJ.

An international research team led by the University of Birmingham's World Health Organization Collaborating Centre for Global Women's Health analyzed data from 140 studies from around the globe that included 14,271 babies born to mothers with COVID-19. They found an overall COVID-19 infection rate of 1.8% (95% confidence interval, 1.2% to 2.5%), as determined by polymerase chain reaction (PCR) testing.

Of the 800 COVID-positive fetuses or babies with outcome data, 20 were stillbirths, 23 died during the first 28 days of life, and 8 were early pregnancy losses; 749 babies (93.6%) were alive at the end of follow-up.

The authors conclude, "Severe maternal covid-19 may be associated with SARS-CoV-2 positivity in babies, but not vaginal delivery, breastfeeding, or mother-baby contact after birth."

Senior author Shakila Thangaratinam, MD, PhD, professor of maternal and perinatal health at the University of Birmingham, said in a university news release, "Ours is the first study to use the World Health Organization's stringent methods to show that it is possible for the virus to be spread from the mother to baby while in the womb, during childbirth, and after delivery.

"However, parents and healthcare professionals can be reassured that only a very small proportion of babies born to mothers with SARS-CoV-2 test positive."

An editorial on the study in the same journal highlights widely varying quality of data among the studies analyzed but echoes Thangaratinam: "Overall, findings from this review seem reassuring."
Mar 17 BMJ study and editorial
Mar 17 University of Birmingham news release

News Scan for Mar 17, 2022

News brief

Hydrogen peroxide contamination tied to less C difficile infection

Implementation of a touchless hydrogen peroxide decontamination system at an acute care hospital was associated with a significant reduction in Clostridioides difficile infection (CDI) rates over a 10-year period, researchers reported today in the American Journal of Infection Control.

The restrospective study compared rates of healthcare-associated CDI at an acute care hospital in Pennsylvania before and after implementation of the aerosolized hydrogen peroxide (aHP) system, a whole-room fogging unit that generates an aerosolized dry-mist fog that covers all surfaces exposed to C difficile spores. The aHP system was used in patient rooms in conjunction with standard bleach cleaning upon discharge or transfer of a CDI patient.

The first study period included 27 months before implementation of aHP (July 2009 to September 2011) and 33 months after implementation (April 2012 to December 2014). The researchers also examined the effects of continued aHP usage over the following 5 years (January 2015 to December 2019).

The before-and-after period showed a reduction in CDI rates from 4.6 per 10,000 patient-days to 2.7 per 10,000 patient-days—a 41% reduction. Over 5 years of continued aHP, CDI rates continue to decline consistently, to 1.4 per 10,000 patient-days. The standardized infection ratio fell from 0.77 in 2015 to 0.5 in 2019.

Although the study authors note they could not account for potential confounders such as hand hygiene compliance, antibiotic usage rates, patient demographics, and cleaning practices, they are confident the aHP system contributed to the decline in CDI rates at the hospital. They suggest future studies should include a large randomized trial of aHP, especially in high-risk environments such as oncology units.
Mar 17 Am J Infect Control abstract

High-path avian flu strikes New Hampshire flock

In ongoing highly pathogenic avian flu activity, federal officials today reported the first detection in a New Hampshire flock, raising the number of states reporting the virus in backyard birds or commercial poultry this year to 16.

In a statement, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Services (APHIS) said New Hampshire's outbreak involves a backyard flock in Rockingham County, which is located in the southeast corner of the state on the Atlantic shore. In earlier waterfowl sampling, 53 positives have been reported, mostly from Rockingham County.

In related developments, the USDA also listed a fourth outbreak in Maine, which, like the previous events, also involves backyard birds. The new outbreak struck a backyard holding that has 173 birds in York County, located in the southern tip of the state on the Atlantic coast.

So far in the United States this year, there have been 38 separate outbreaks in backyard bird or commercial poultry. The detections in poultry and wild birds involved the Eurasian H5N1 strain that has also spread to other parts of the world and has been confirmed in one human infection.
Mar 17 USDA statement on high-path avian flu in New Hampshire
USDA wild bird avian flu page
USDA poultry outbreak page

Experimental drug for Creutzfeldt-Jakob disease shows some promise

A potential treatment for the prion infection known as Creutzfeldt-Jakob disease (CJD), developed by UK scientists, has shown "very encouraging" early results in six patients at University College London Hospitals (UCLH), according to a study yesterday in The Lancet Neurology.

Researchers at the MRC Prion Unit at UCL developed a monoclonal antibody called PRN100 that was administered to six UCLH patients with CJD—four women and six men—from October 2018 to July 2019.

CJD is a rare, always-fatal disease that causes brain damage and for which there is no licensed treatment. Most patients die within a few months of diagnosis.

Disease progression in three patients who received the drug appeared to stabilize, the study authors said, and none experienced side effects. Unfortunately, however, all six still died from CJD.

The study authors conclude, "These findings justify the need for formal efficacy trials in patients with CJD at the earliest possible clinical stages and as prophylaxis in those at risk of prion disease."

Senior author John Collinge, MD, who directs the MRC Prion Unit at UCL and led the development of the PRN100 treatment, said in a UCL press release, "Drugs used to treat other diseases have been tried experimentally in treating CJD in the past, but none has had an impact on disease progression or mortality. This is the first time in the world a drug specifically designed to treat CJD has been used in humans, and the results are very encouraging.

"While the number of patients we treated was too small to determine whether the drug altered the course of the disease, this is nevertheless an important step forward in targeting prion infections."

In a commentary in the same journal, German neurologist Inga Zerr, MD, wrote, "These outcomes are very encouraging and long awaited but, in light of the limitations, such as the small number of patients included and the use of historical controls, these results must be considered preliminary."
Mar 16 Lancet Neurol study and commentary
Mar 17 University College London press release