News Scan for Aug 15, 2022

News brief

Novavax applies for COVID booster EUA as UK approves 2-strain booster

Following the Food and Drug Administration (FDA) emergency use authorization (EUA) of the Novavax COVID-19 vaccine last month for the primary vaccine series, the company announced today that it has applied for an EUA for the vaccine to also be used as a booster in adults ages 18 and older.

In an announcement today, Novavax said if authorized, the vaccine would be the first protein-based COVID-19 booster for adults. It said its application covers both heterologous (different-brand) and homologous (same-brand) booster strategies.

Stanley Erck, Novavax's president and chief executive officer, said, "It's important for people to have a choice as they evaluate how to stay protected against COVID-19, and boosters are an invaluable tool to build upon immunity obtained from previous vaccinations."

A phase 3 study found that the third dose produced robust antibody responses that met or exceeded levels seen in the primary series. The vaccine also prompted a significant antibody response when used as a heterologous booster.

Local and systemic responses lasted about 2 days and showed an increasing incidence across all three doses. Rare instances of myocarditis, pericarditis, and anaphylaxis have been reported outside of clinical trials, and, earlier this month, the European Medicines Agency recommended that the vaccine maker carry a warning about the two heart conditions.
Aug 15 Novavax press release

In other vaccine developments, the UK Medicines and Healthcare Products Regulatory Agency today approved Moderna's bivalent (two-strain) booster shot, which covers the original SARS-CoV-2 virus plus the Omicron BA.1 variant. The group said it based its findings on clinical trials that showed the booster prompted a strong immune response against BA.1 and the original virus and a good response against Omicron BA.4 and BA.5 subvariants.

The United Kingdom is the first to approve a bivalent booster vaccine. Companies that make mRNA vaccines are working on bivalent booster shots for the US market that target BA.4 and BA.5.
Aug 15 MHRA statement

Easing rules for gatherings, vaccine proof tied to Omicron spike in Korea

Dialing back rules for social gatherings and COVID-19 vaccine passes in South Korea was tied to a record spike in SARS-CoV-2 Omicron variant infections in March 2022, according to an observational study published late last week in JAMA Network Open.

Researchers in South Korea mined daily data on COVID-19 cases and the proportion of Omicron infections from Dec 1, 2021, to Mar 16, 2022. They multiplied the number of daily cases by the rate of positive Omicron tests to arrive at a proxy of variant activity in the community.

In mid-January 2022, the country relaxed restrictions on social gatherings, stopped requiring proof of COVID-19 vaccination in public facilities, expanded community screening, and mandated screening for all schoolchildren.

The Rt, or the average number of cases resulting from a single infected person, was greater than 1 throughout the study period, indicating uncontrolled viral transmission. The easing of limits on social gatherings was linked to an increase in Rt of 20.4% (95% confidence interval [CI], 5.8% to 36.5%), and suspension of COVID-19 vaccine passes was tied to a jump in Rt of 10.9% (95% CI, 3.2% to 24.8%).

The use of community COVID-19 screening centers and mandatory screening in schools, however, was associated with declines in Rt of 16.8% (95% CI, -25.2% to -11.1%) and 18.8% (95% CI, -22.2% to -11.1%), respectively.

The study authors noted that South Korea had successfully controlled SARS-CoV-2 transmission through the use of public health and social measures (PHSMs) without lockdowns in 2020 and 2021, but the world-record spike of 600,000 new daily Omicron cases occurred soon after these measures were relaxed.

The screening protocols appeared to help slow the spread of the virus, they said, but "our finding of a mean R_t greater than 1 during the study period suggested there may have been difficulty in controlling the COVID-19 pandemic in South Korea. The findings suggest awareness of R_t can inform policy planning and practice, including by allowing timely implementation and relaxation of PHSMs."
Aug 12 JAMA Netw Open research letter

FDA green-lights baloxavir use for flu in kids as young as 5

Roche recently announced that the FDA has approved the use of baloxavir marboxil (Xofluza) for treating flu in children ages 5 to 12. Also, the FDA approved the drug for postexposure prophylaxis (prevention) in kids ages 5 to 12 who had contact with someone with flu.

Baloxavir marboxil was first approved for use as a single-dose treatment for uncomplicated flu for people ages 12 and older in 2018, the first new antiviral to be approved by the FDA in two decades. Two years later the FDA approved the use of the drug for postexposure prophylaxis.

Levi Garraway, MD, PhD, Roche's chief medical officer and head global product development, said that, despite the ongoing COVID-19 pandemic, flu is still a public health threat, and effective flu antivirals are a critical tool for easing the burden on healthcare systems.
Aug 12 Roche press release

Salmonella linked to backyard poultry sickens 312 more people

In its latest update on a Salmonella outbreak linked to backyard poultry, the Centers for Disease Control and Prevention (CDC) reported 312 more cases, raising the nation's total to 884 in 48 states.

The CDC also said one illness has now been reported in the District of Columbia. The five states with the most cases are California (59), Minnesota (46), Texas (45), Wisconsin (41), and Missouri (36).

Two more Salmonella subtypes—I 4,[5],12:i:- and Indiana—were added to the outbreak, bringing the total to seven. The previously announced strains are Enteritidis, Hadar, Infantis, Mbandaka, and Typhimurium.

Patient ages range from 1 to 102, and 55% are female. The latest illness onset was Jul 23. Of cases with available outcome data, 158 people were hospitalized. The number of deaths held steady at 2.

People bought poultry from 177 retail locations across 41 states. Some bought poultry from more than one location. Testing by health officials in four states have identified the outbreak strains in poultry and poultry environments, people's homes, and stores. They are New Mexico, North Dakota, Tennessee, and Wisconsin.

Whole-genome sequencing of 904 samples from sick people, animals, and the environment to identify risk of antibiotic resistance found that 40.6% were resistant to 13 key antibiotics. Though most people with Salmonella infections recover without antibiotics, the CDC said some illnesses would be difficult to treat with recommended drugs and would require a different antibiotic choice.
Aug 12 CDC Salmonella outbreak update

Stewardship / Resistance Scan for Aug 15, 2022

News brief

VHA program tied to improved antibiotic use for respiratory infections

A clinician-directed intervention implemented at facilities in the Veterans' Healthcare Administration (VHA) was associated with better management of, and reduced antibiotic prescribing for, acute respiratory infections (ARIs), researchers reported today in Infection Control & Hospital Epidemiology.

The ARI Campaign, implemented in 2017 by the VHA's Antimicrobial Stewardship Taskforce to reduce unnecessary antibiotic prescribing for ARIs, encourages Veterans' Affairs (VA) hospitals to engage high-prescribing physicians with two strategies: audit and feedback with peer comparison of ARI antibiotic prescribing rates, and individualized academic detailing of ARI management. To evaluate the effectiveness of the ARI Campaign, researchers with the VA and the Centers for Disease Control and Prevention (CDC) calculated the probability of receiving antibiotics for an ARI before and after implementation (October 2012 through March 2019). Secondary outcomes included probability of a return clinic visit or infection-related hospitalization.

Comparing 1,003,509 and 323,023 uncomplicated ARI visits before and after implementation, respectively, the researchers found the probability of receiving antibiotics for ARI decreased 18% after implementation (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.78 to 0.86). Facilities with the highest quartile of intervention intensity demonstrated larger reductions in antibiotic prescribing (OR, 0.69; 95% CI, 0.59 to 0.80) compared to nonparticipating facilities (OR, 0.89; 95% CI, 0.73 to 1.09).

Return visits (OR, 1.00; 95% CI, 0.94 to 1.07) and infection-related hospitalizations (OR, 1.21; 95% CI, 0.92 to 1.59) were not different before and after implementation within facilities that performed intensive implementation.

"The findings suggest that implementation of the clinician-directed intervention was associated with improvements in guideline-concordant ARI management," the study authors concluded.
Aug 15 Infect Control Hosp Epidemiol abstract

Antibiotic stewardship education linked to improved dental antibiotic use

The first US antibiotic stewardship intervention for private practice dentists was associated with fewer antibiotic prescriptions and significant improvements in appropriate antibiotic prescribing, researchers reported last month in Open Forum Infectious Diseases.

In a prospective multipractice cohort study, a team led by Ohio State pharmacists and clinicians recruited private practice dentists for a four-phase dental antibiotic stewardship initiative. The four phases included collection of baseline antibiotic use data and a pre-education survey to establish the level of knowledge about antibiotic stewardship, three interactive education sessions conducted by infectious disease and antibiotic stewardship program (ID ASP) experts, 3 months of audit and weekly feedback with 1-on-1 consults for dentists who prescribed antibiotics inappropriately, and a post-education survey.

Outcomes assessed included overall antibiotic prescribing, antibiotic appropriateness, and antibiotic duration before and after education.

Fifteen dentists participated, 10 of whom had practiced for more than 20 years. The pre-education survey found 14 were unfamiliar with dental antibiotic stewardship. While procedures over the study period increased from 8,526 to 9,203, the number of antibiotic prescriptions pre/post-education decreased 14.5%, from 2,124 to 1,816. Overall, the proportion of appropriate antibiotic use (both for treatment and prevention) increased from 19% to 87.9% pre/post-education, with appropriate prophylactic antibiotic use improving from 46.6% to 76.6% and appropriate use of treatment antibiotics improving from 15% to 90.2%.

In addition, antibiotic duration pre/post-education decreased from 7.7 days to 5.1 days, and use of clindamycin declined 90%. The post-education survey responses recommended making antibiotic stewardship a required annual continuing education component.

"Similar to antibiotic stewardship in hospitals, simply asking physicians or dentists to do a better job at prescribing antibiotics does not work," the study authors wrote. "After learning dental antibiotic stewardship from ID ASP experts, dentists rapidly optimized antibiotic use."

The authors also note that they have since been invited to speak about dental antibiotic stewardship at local and national study clubs and dental societies.
Jul 25 Open Forum Infect Dis study