A new study out of Japan suggests that seasonal flu vaccination is associated with less unnecessary antibiotic use in people over 65, researchers reported late last week in the Journal of Antimicrobial Chemotherapy.

Using data from the Vaccine Effectiveness, Networking, and Universal Safety study database, which includes all claims data and vaccination records from the 2015-16 through 2020-21 flu seasons, researchers with Japan's National Center for Global health and Medicine examined the association of vaccination status with the frequency of antibiotic prescription, frequency of healthcare facility consultation, risk of admission to a hospital, and risk of death in the follow-up period for the same season (January 1 to March 31). They focused on patients ages 65 and older who visited any healthcare facility with an upper respiratory infection (URI), comparing vaccinated to unvaccinated patients.

50% lower rate of hospital admission

A total of 244, 642 people were enrolled in the study. Modified Poisson regression analyses showed that seasonal influenza vaccination was associated with a lower risk ratio (RR) for the frequency of antibiotic prescription (RR, 0.98; 95% confidence interval [CI] 0.96 to 1.0), higher RR for the frequency of healthcare facility visits (RR 1.12; 95% CI 1.11 to 1.12), lower rate of admission (RR 0.51; 95% CI 0.48 to 0.54), and lower risk for death (RR 0.39; 95% CI 0.30 to 0.51). 

Analysis of 101, 734 people with matched propensity score data in each of the unvaccinated and vaccinated groups showed that the average treatment effect of vaccination was −0.004 (95% CI −0.006 to −0.002) for the frequency of antibiotic prescription, −0.005 (−0.007 to −0.004) for the frequency of healthcare facility consultation, −0.001 (−0.002 to −0.001) for the risk of admission and 0.00 (0.00 to 0.00) for the risk of death.

"Our results suggest that the seasonal influenza vaccine might help to reduce inappropriate AMU [antimicrobial use] for URIs, although care should be taken when interpreting the results," the study authors wrote. "This indirect benefit would be another reason to recommend seasonal influenza vaccination to the general population to enhance AMR [antimicrobial resistance] countermeasures in society."

In a recent respiratory virus update, the US Centers for Disease Control and Prevention (CDC) said it is monitoring the spread of BA.2.86, as well as JN.1, a SARS-CoV-2 variant that is part of the same lineage and contains an extra spike mutation.

Scientists have been tracking BA.2.86 because of its numerous mutations, and in recent weeks, they identified JN.1 as a related variant that has the L455S mutation, which has concerning immune-evasion properties. Some have seen signs of a growth advantage in a few European countries.

JN.1 was detected in the United States in September and has also been identified in 11 other countries, the CDC said. It added that nearly all viruses circulating in the United States now are part of the XBB family and that JN.1 makes up less than 0.1% of SARS-CoV-2 viruses.

For as long as we have COVID-19, we’ll have new variants.

The CDC said initial data suggest that updated COVID vaccines will help protect against BA.2.86, and it expects a similar effect against JN.1. It also said an analysis from the federal government’s SARS-CoV-2 Interagency Group suggests treatments and testing will remain effective.

"For as long as we have COVID-19, we’ll have new variants. Nearly all represent relatively small changes compared with previous variants. CDC and other agencies monitor for impacts of new variants on vaccines, tests, and treatments, and will alert the public quickly if anything concerning is detected," the CDC said.

The US Food and Drug Administration (FDA) on October 27 warned consumers to avoid buying and stop using 26 over-the-counter eye drop products, including some from major chain stores, owing to potential infection risk.

So far, no illnesses have been reported. However, inspection at the manufacturing facility, not named in the FDA statement, turned up "insanitary" conditions and positive bacterial results from environmental samples in critical drug production areas. The products are intended to be sterile.

Products on the FDA's list include eye lubricants and dry-eye relief. The FDA said it urged the manufacturer to recall the products on October 25. The eye drops are marketed under six brands, including CVS Health, Leader (Cardinal Health), Rugby (Cardinal Health), Rite Aid, Target Up and Up, and Velocity Pharma.

The FDA said CVS, Rite Aid, and Target are removing the products from their shelves and websites, but eye drops under the Leader, Rugby, and Velocity brands may still be available for purchase in stores and online.

By July 2023, more than 80% of residents of Lower Mainland, British Columbia (BC), younger than age 50 had been infected with SARS-CoV-2 and may have some protection against infection, but more than 40% of those aged 80 or older remained uninfected and thus were at highest risk for hospitalization and death, according to a study today in CMAJ.

In their ninth survey of the presence of SARS-CoV-2 antibodies among Lower Mainland residents, a team led by BC Centre for Disease Control researchers estimated infection-hospitalization rates (IHRs) and infection-fatality rates (IFRs) by age and sex for the sixth to seventh (Delta/Omicron-BA.1 variants), seventh to eighth (Omicron BA.2/BA.5), and eighth to ninth (Omicron BA.5/BQ.1) surveys. 

"About 10%, 40% and 60% of residents were infected with SARS-CoV-2 by the sixth (September 2021), seventh (March 2022) and eighth (July 2022) serosurveys," the study authors wrote. "We conducted the ninth (December 2022) and tenth (July 2023) serosurveys and sought to assess risk of severe outcomes from a first-ever SARS-CoV-2 infection during intersurvey periods."

1 in 30 elderly may be hospitalized

By July 2023, SARS-CoV-2 seroprevalence was higher than 80% among adults younger than 50 years but less than 60% among those aged 80 and older.

We estimated about 1 hospital admission for COVID-19 per 300 newly infected children younger than 5 years versus about 1 per 30 newly infected adults aged 80 years and older, with no deaths from COVID-19 among children but about 1 death per 80 newly infected adults aged 80 years and older.

Period-specific IHRs and IFRs were consistently less than 0.3% and 0.1%, respectively. Age-specific IHRs and IFRs among all adults were less than 1.0% to 0.1%, respectively, but were 3.3% and 1.0% among those 80 and older (IHRs, 4.7%, 2.2% and 3.5%; IFRs, 3.3%, 0.6% and 1.3% during the sixth to seventh, seventh to eighth, and eighth to ninth periods, respectively).

"During the eighth to ninth period, we estimated about 1 hospital admission for COVID-19 per 300 newly infected children younger than 5 years versus about 1 per 30 newly infected adults aged 80 years and older, with no deaths from COVID-19 among children but about 1 death per 80 newly infected adults aged 80 years and older during that period," the researchers wrote.