Analysis shows last year’s flu vaccine 36% protective against H3N2 strain

News brief

A new CDC analysis of 2021-22 data reveals that flu vaccine effectiveness (VE) against the H3N2 (influenza A) strain for all ages was 36%. The study was published today in Clinical Infectious Diseases.

The study was based on outpatients seen at seven clinic sites across the United States from October 2021 to April 2022. Research staff across the sites enrolled patients aged 6 months or older seeking outpatient care for acute respiratory illness with cough.

Patients who tested positive for SARS-CoV-2 were excluded from VE estimations.

In total, out of 6,260 participants, 468 (7%) tested positive for influenza only, including 440 (94%) for H3N2; after removing patients with COVID-19, 4,312 patients were included in analyses of influenza VE, with 2,463 (57%) vaccinated against influenza.

The effectiveness against H3N2 was 36% (95% confidence interval, 20% to 49%) overall in patients aged 50 years or younger.

"We were unable to detect statistically significant protection against laboratory-confirmed influenza among adults aged 50 years and older," the authors said. "Detection of statistically significant VE below 30% with high vaccine coverage requires a larger sample size than we were able to enroll this season."

In 6 countries, most COVID deaths occurred in seniors, men with seasonal patterns

News brief

An analysis of the evolution of COVID-19 deaths in six countries in 2020 and 2021 identifies substantial inter-country differences, with variations by age, sex, and season.

In the study, published late last week in the International Journal of Infectious Diseases, French researchers parsed data on deaths by age and sex from the Demography of COVID-19 Deaths and the Human Mortality databases from March 2020 to February 2022. The included countries were Belgium, England and Wales, France, Scotland, Sweden, and the United States, although France had no available data after Dec 24, 2021.

Highest total deaths were in US

The first wave of the pandemic began in March 2020 and peaked in April 2020, with a standardized weekly death rate (SDR) of 164 per 1 million in Belgium, 149 in England and Wales, 127 in Scotland, 90 in France, 70 in Sweden, and 62 in the United States. Fewer deaths occurred in summer and early fall 2020, except in the United States, which saw a new wave beginning in June.

During the second wave, the SDR rose rapidly in Belgium, climbing from 8 per 1 million in September 2020 to 120 in November. England and Wales had the highest SDR, reaching 162 per 1 million in January 2021.

In spring and summer 2021, SDRs stabilized, and that fall and winter, the rate slowed substantially in all countries except the United States. While the US SDR didn't surpass 100 during the study period, it didn't decline to near 0 in the summer, unlike in European countries. The SDR was highest in all countries in winter, and a larger proportion of men died than women.

By February 2022, the United States had the highest total death toll, which was during the Omicron-dominant period, followed by England and Wales. Among residents aged 44 years and younger, distinct wave patterns were seen only in England, Wales, and the United States. SDR peaks occurred in those aged 75 and older in all countries.

By February 2022, the United States had the highest total death toll.

"The United States was more heterogeneous in terms of each wave's beginning as well as the types and timing of public health strategies implemented by local governments to contain the spread of the virus," the authors wrote.

Inappropriate diagnosis, treatment of urinary infections in patients with neurologic injuries

News brief

A study of four Veterans Affairs (VA) hospitals found that almost a third of urinary tract infection (UTI) diagnoses are inappropriate in patients with neurogenic bladder (NB), researchers reported late last week in Antimicrobial Stewardship & Healthcare Epidemiology.

For the retrospective study, VA researchers analyzed data on veterans with NB—the name given to a number of urinary conditions in patients who lack bladder control because of a brain or spinal cord injury—who were hospitalized with a UTI or asymptomatic bacteriuria (ASB) diagnosis from Jan 1, 2017, to Dec 31, 2018. Many NB patients require urinary catheters, which have been linked to chronic bacteriuria and UTIs. While ASB is commonly mistaken for UTI and treated inappropriately with antibiotics, no studies have looked specifically at patients with NB and suspected UTI, the authors said.

Each patient was evaluated for appropriateness of diagnosis based on national guidelines, with researchers comparing outcomes in those who received appropriate and inappropriate diagnosis and treatment.

The study included 170 encounters with ASB (30%) or UTI (70%) occurring in 166 patients (86% males). While all ASB diagnoses were appropriate, and 96.1% had appropriate treatment, 31.1% of UTI had inappropriate diagnoses and 51.3% received inappropriate treatment. Among patients with spinal cord injury/disorder (SCI/D) or multiple sclerosis, appropriate diagnosis and treatment was associated with significantly longer post-culture hospital stays (median, 14 vs 7 days), but no other outcomes were significantly associated with appropriate versus inappropriate ASB or UTI diagnosis or treatment.

"Our study provides further support for implementing diagnostic stewardship interventions, specifically targeting hospitalized patients with NB," the study authors wrote, adding that stewardship interventions should prioritize settings such as inpatient rehabilitation, long-term care facilities, and SCI/D units. 

Measles cases rise in Ohio—73 cases total

News brief

Ohio has 10 more measles cases in a Columbus-area outbreak. Officials have now confirmed 73 cases, and 26 of those patients required hospitalization.

Of the case-patients, 67 were unvaccinated, 4 were partially vaccinated (with one of two doses of the measles, mumps, rubella [MMR] vaccine), and 2 had unknown vaccination status. No cases have been seen in children who are fully vaccinated.

Seventy percent of the cases are confirmed in children ages 1 to 5, with 33 cases among 1- and 2-year-olds. Seventeen cases have been seen in infants under the age of 1. Eighteen cases have been recorded children ages 3 to 5 years, with 5 cases in kids ages 6 to 17 years. Thirty-seven cases have appeared in females, and 36 in males.

The first case-patient developed a rash on Oct 22.

The MMR vaccine is given in two doses, the first between the ages of 12 and 15 months, and the second between 4 and 6 years.

According to the Centers for Disease Control and Prevention (CDC), "One dose of MMR vaccine is 93% effective against measles, 78% effective against mumps, and 97% effective against rubella. Two doses of MMR vaccine are 97% effective against measles and 88% effective against mumps."

This week's top reads