Flu Scan for Feb 15, 2018

News brief

High-dose vaccine more likely to protect against lab-confirmed flu

The high-dose flu vaccine is 38% more effective in protecting elderly people against laboratory-confirmed influenza than the standard-dose vaccine, according to a study of Veterans Health Administration (VHA) senior patients published yesterday in the Journal of Infectious Diseases.

The study involved VHA patients 65 years of age or older during the 2015-16 influenza season. To conduct the study, 9,091 standard-dose and 24,682 high-dose recipients were matched using electronic medical records.

In addition to its 38% advantage against lab-confirmed flu, the high-dose vaccine was 25% more effective in preventing influenza- or pneumonia-associated hospitalization, 7% more effective against all-cause hospitalization, and 14% more effective against influenza- or pneumonia-associated outpatient visits.

Seniors are one of the most at-risk population for complications from seasonal flu infections, including hospitalization. The authors said their study adds to a growing body of literature that suggests the high-dose vaccine should be used in senior populations.

"In protecting senior VHA patients against influenza- or pneumonia-associated hospitalization, a high-dose influenza vaccine was more effective than standard-dose vaccine," the authors concluded.
Feb 14 J Infect Dis study

CDC says flu sickens up to 35 million people in a season

Centers for Disease Control and Prevention (CDC) experts analyzed data from six recent flu seasons and determined that the number of influenza-related illnesses during each season ranged from 9.2 million to 35.6 million, including 140,000 to 710,000 influenza-related hospitalizations. Their findings were published in Influenza and Other Respiratory Viruses.

The six seasons analyzed (2010-11 through 2015-16) followed the 2009 pandemic year, and to conduct the study researchers used information gathered from the Influenza Hospitalization Surveillance Network, among other databases.

People over the age of 65 represented the greatest number of flu hospitalizations, ranging from 87,000 to 523,000. Children ages 5 to 17 years were the least likely to be hospitalized for influenza. Seasons 2012-13 and 2014-15 had the most activity.

The authors also used vaccine effectiveness estimates for each season to estimate how many illnesses the vaccines prevented, which reached a peak in 2013-14, when an estimated 86,730 hospitalizations were averted. CDC data show vaccine effectiveness that year of about 51%.

The authors of the study said annual estimates of influenza burden of disease, including related hospitalizations, can help with public health decision making, vaccine production, and disease surveillance.

"Burden estimates are invaluable for estimating the economic and societal costs of influenza and making decisions about procurement of vaccines and influenza antivirals before the influenza season begins," the authors concluded.
Feb 14 Influenza Other Respir Viruses study
CDC 2013-14 flu data

News Scan for Feb 15, 2018

News brief

CDC declares coconut-linked Salmonella investigation over

The Centers for Disease Control and Prevention (CDC) said today that a multistate Salmonella outbreak—first announced a month ago—appears to be over after it reached 27 cases in nine states.

Today's update includes two new cases—in California and Washington—since the CDC's first outbreak notice on Jan 16. Six patients required hospitalizations, but no deaths were reported. Also, the most recent illness-onset date is Nov 4, 2017, with the earliest more than a year ago. Patients range in age from 1 to 82 years, with a median age of 15.

Whole-genome sequencing revealed that Salmonella strains infecting outbreak patients were closely related genetically. None, however, were shown to be antibiotic resistant.

On Jan 3, Evershing International Trading Company of San Jose, Calif., recalled all 16-ounce Coconut Tree Brand Frozen Shredded Coconut after Massachusetts officials confirmed Salmonella in the product.

"This outbreak appears to be over," the CDC said. "However, the recalled shredded coconut has a long shelf life and may still be in people’s homes. Consumers unaware of the recall could continue to eat the product and potentially get sick."
Feb 15 CDC notice
Jan 17 CIDRAP News story "Frozen coconut implicated in new Salmonella outbreak"

Survey of valley fever cases since 1940 highlights environmental exposure

Between 1940 and 2015, officials recorded 47 coccidioidomycosis, or valley fever, outbreaks worldwide that resulted in 1,464 cases, new research published in Emerging Infectious Diseases shows. The vast majority of those cases, 85%, were caused by environmental exposures to soil containing the fungi that causes the disease.

Though valley fever is endemic to the southwestern United States, there have been few attempts to look at overall exposure trends in the literature. The authors of this study searched all medical literature that documented more than 2 human coccidioidomycosis cases (at least 1 lab-confirmed) linked to a common source, event, or activity in space and time, to better understand the environmental risk factors of valley fever infection.

Outbreaks ranged in size from 2 to 379 cases. Two outbreaks (4%) resulting in 582 cases (40%): One occurred after the Northridge earthquake in 1994 in Ventura County, and the other resulted from the "Tempest from Tehachapi" dust storm in 1977, both in California.

Over half of the outbreaks (53%) occurred because of an occupational exposure, usually construction or farming. Military personnel, incarcerated persons, and outdoor workers had the highest risk of infection.

"Over time, outbreak investigations uncovered additional coccidioidomycosis-endemic areas throughout California's Central Valley, Texas, Utah, and areas of Brazil," the authors said. "Outbreak data also suggest that some geographic regions seem particularly well suited for Coccidioides growth and human exposure. For example, the arid hills bordering the southwestern portion of California's Central Valley were the setting for 5 outbreaks within 150 miles of each other."

Each year in the United States, about 10,000 non-outbreak cases of valley fever are recorded, and there are likely hundreds more that go unreported, the authors said. Symptoms are flu-like, including fever, cough, chills, and chest pain. Most cases resolve on their own.
Feb 14 Emerg Infect Dis study