News Scan for Jan 12, 2022

News brief

US COVID vaccination may have saved 240,000 lives in first 6 months

The US COVID-19 vaccination program may have averted 14 million infections, saved more than 240,000 lives, and prevented upwards of 1.1 million hospitalizations in the first half of 2021, according to estimates from a modeling study yesterday in JAMA Network Open.

Led by York University scientists in Toronto, the research team simulated the pandemic trajectory under two scenarios: no vaccinations and a program that reached only half the actual daily vaccination rate. Total infections, hospitalizations, and deaths under each scenario from Dec 12, 2020, to Jun 30, 2021, were compared with simulated trends under US vaccination campaigns.

The researchers didn't consider waning vaccine immunity or recovery from COVID-19 in their estimations.

Relative to the no-vaccination scenario, the actual US vaccination campaign prevented upwards of 14 million COVID-19 infections, saved an estimated 240,797 lives (95% credible interval [CrI], 200,665 to 281,230), and prevented 1,133,617 hospitalizations (95% CrI, 967,487 to 1,301,881).

COVID-19 vaccination may have also averted a wave of infections driven by the Alpha (B117) variant in April 2021. The wave was projected to have led to 4,409 deaths (95% CrI, 2,865 to 6,312) and 17,979 hospitalizations (95% CrI, 13,191 to 23,219).

Under the scenario of daily vaccination rates of half that of the reported rate, another 77,283 (95% CrI, 48,499 to 104,519) deaths may have occurred, along with 336,000 more hospitalizations (95% CrI, 225,330 to 440,109).

"Our analytical model suggested that the US COVID-19 vaccination program was associated with a reduction in the total hospitalizations and deaths by nearly half during the first 6 months of 2021," the researchers wrote.

"As new variants of SARS-CoV-2 continue to emerge, a renewed commitment to vaccine access, particularly among underserved groups and in counties with low vaccination coverage, will be crucial to preventing avoidable COVID-19 cases and bringing the pandemic to a close."
Jan 11 JAMA Netw Open research letter


Researchers develop wearable air sampler to detect COVID-19 exposure

Yale University researchers have developed a wearable passive air sampler to monitor personal exposure to COVID-19, they reported yesterday in Environmental Science & Technology Letters.

The polydimethylsiloxane (PDMS)-based air sampler, the Fresh Air Clip, continually monitors exposure to virus-containing aerosols, which could prove helpful to workers in high-risk settings such as healthcare. While active indoor air sampling devices are available, they are usually large, expensive, and nonportable, and they require electricity, the authors noted. Passive samplers, however, can be small, lightweight, portable, and inexpensive.

The researchers tested the air sampler in a rotating drum containing aerosols laden with a surrogate virus similar to SARS-CoV-2. They found virus in the sampler through polymerase chain reaction (PCR) testing, demonstrating its ability to estimate airborne virus levels.

When 62 volunteers wore the samplers for 5 days, PCR detected SARS-CoV-2 RNA in 5 (8%) of them, 4 of them worn by restaurant servers and 1 by a homeless shelter worker. The highest viral loads (more than 100 RNA copies per clip) were found in two clips worn by restaurant servers.

While the Fresh Air Clip hasn't been commercialized, the study authors said it could be used as a semiquantitative screening tool for monitoring personal COVID-19 exposure and as a way to identify high-risk areas for indoor exposure.

"Our findings demonstrate that PDMS-based passive samplers may serve as a useful exposure assessment tool for airborne viral exposure in real-world high-risk settings and provide avenues for early detection of potential cases and guidance on site-specific infection control protocols that preempt community transmission," they wrote.
Jan 11 Environ Sci Technol Lett study


Global flu levels starting to resemble pre-COVID pattern

Global flu activity is still low, but is rising, with numbers at pre–COVID-19 pandemic levels for this time of year in several Northern Hemisphere countries, the World Health Organization (WHO) said this week in its latest global flu update, which covers the middle weeks of December.

Given the increased flu circulation amid brisk COVID-19 activity, the WHO urged countries to enhance surveillance for both diseases and to step up their flu vaccination campaigns.

H3N2 influenza is still the dominant strain in most parts of the world, except for China, where activity is rising with influenza B as the most common strain.

In the Southern Hemisphere, flu activity remained low in much of the temperate region, though some South American countries reported increasing H3N2 detections.

Globally, of respiratory samples that tested positive for flu during the middle of December, 73.6% were influenza A and 26.4% were influenza B. Of subtyped influenza A viruses, 95.6% were H3N2. Of characterized influenza B viruses, nearly all belonged to the Victoria lineage.
Jan 10 WHO global flu update


Multistate Salmonella outbreak tied to bearded dragon pets sickens 44

The US Centers for Disease Control and Prevention (CDC) said that it and state partners are investigating a Salmonella Uganda outbreak linked to contact with pet bearded dragons that has sickened 44 people from 25 states since December 2020.

Bearded dragons have been linked to other Salmonella outbreaks in the past, most recently a Salmonella Muenster outbreak in 2020 that made 18 people sick in 11 states.

In the latest outbreak, Oregon officials collected samples in November 2021 from a sick person's home, with the strain from a bearded dragon matching the strain that made the patient sick. Using PulseNet, the national sequencing database, health investigators identified other cases, with illness onsets from Dec 24, 2020, to Dec 2, 2021.

Eight patients were children younger than 5. Of 37 cases with available information, 15 were hospitalized. No deaths were reported.

Of 33 people interviewed about possible exposures, 21 reported owning or touching bearded dragons or their supplies. People bought their bearded dragons from various sources, including locally and online.

Whole-genome sequencing of bacteria from 44 people and 1 bearded dragon demonstrated no antibiotic resistance.
Jan 11 CDC Salmonella outbreak notice
Oct 1, 2020, CIDRAP News
Nov 24, 2020, CDC
final outbreak notice

Stewardship / Resistance Scan for Jan 12, 2022

News brief

Study highlights inappropriate prescribing for respiratory infections

A study of 42 million US patient visits for antibiotic-inappropriate acute respiratory infections (ARIs) found that more than 10% received an antibiotic prescription, with providers in urgent care clinics and southern states among the most likely prescribers, US researchers reported this week in Infection Control & Hospital Epidemiology.

The study, conducted by researchers from the Centers for Disease Control and Prevention and IQVIA using IQVIA's medical claims and prescription databases, looked at 41.97 million patient visits from October 2018 through September 2019 with diagnosis codes for ARIs for which antibiotics are generally not indicated. These included asthma, allergy, bronchitis, bronchiolitis, flu, viral upper respiratory infection, and non-suppurative otitis media (earache).

The researchers calculated the Prescriber Inappropriate Antibiotic Prescribing Index (PIAPI) as the proportion of a clinician's visits for antibiotic-inappropriate ARIs that received an antibiotic, and used a machine-learning model to determine drivers of PIAPI.

The average PIAPI was 11%, meaning that clinicians prescribed antibiotics in 11% of visits for which the drugs were unnecessary. The machine-learning model identified outpatient setting, patient-age mix, and state as the strongest predictors of PIAPI. Among settings, average PIAPI ranged from 5% in outpatient hospital clinics to 21% in urgent care facilities. Clinicians who saw children predominantly had a lower average PIAPI (7%) than those who saw adults or balanced age mixes (11%–13%). The researchers also detected wide variation by state, with the highest average PIAPIs in southern states, including Mississippi (17%) and Alabama (18%).

"This project demonstrated that machine-learning may be valuable in targeting antibiotic stewardship interventions," the study authors wrote.
Jan 10 Infect Control Hosp Epidemiol abstract


Mass azithromycin distribution in Niger tied to reduction in Shigella in kids

A study of children in Niger who received biannual administration of azithromycin found a substantial reduction in Shigella carriage after 2 years, researchers reported this week in Clinical Infectious Diseases.

In the study, researchers from the United States and Niger analyzed rectal samples from children in 30 villages in Niger that had participated in the MORDOR I trial, which randomized children in Niger, Malawi, and Tanzania to receive biannual administration of azithromycin or placebo. Using polymerase chain reaction (PCR) assays, the researchers screened the samples for 29 enteropathogens at baseline and at 24 months.

At baseline, five pathogens had a baseline prevalence of greater than 2%: enteroaggregative Escherichia coli (21.7%), Shigella (14.1%), Campylobacter jejeuni or Campylobacter coli (12.9%), enterotoxigenic E coli (11.8%), and typical enteropathogenic E coli (3.8%). There were no differences in pathogen quantity by trial arm.

At 24 months, however, the prevalence of Shigella in samples from the villages randomized to azithromycin was 64% lower than those from placebo villages (prevalence ratio, 0.36; 95% confidence interval [CI], 0.17 to 0.97), corresponding to an absolute prevalence difference of –11.1% (95% CI, –19.4% to –2.8%). No other differences in pathogen quantity or prevalence were observed.

The study authors say the findings could partly account for the 18.1% reduction in mortality observed in the Niger cohort in the MORDOR I trial, which was the largest mortality reduction observed among the three countries in the study. In addition, they note that analysis of verbal autopsies conducted in Niger following MORDOR I have found reductions in incidence and deaths from dysentery, which can be caused by Shigella.

"In summary, we found a significant reduction in Shigella carriage from a high baseline among children 1-59 months of age in villages that received biannual azithromycin instead of placebo," they wrote. "Together with reports demonstrating a substantial decrease in dysentery incidence, these findings suggest that a reduction in Shigella infections may have contributed to the observed reduction in mortality."
Jan 10 Clin Infect Dis abstract
Apr 26, 2018 CIDRAP News scan on MORDOR trial

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