Influenza B exerts muscle over receding US flu season
Markers for the US flu season showed some further declines last week, with the percentage of clinic visits for flulike illness falling below the national baseline for the first time after 19 weeks at or above baseline, the US Centers for Disease Control and Prevention (CDC) said today in its weekly update.
Five regions, however, are still above their baselines for that indicator.
The percentage of respiratory specimens that tested positive for flu fell slightly, from 10.8% to 10.7%, and an increasing proportion are influenza B, which now makes up 86% of the flu specimens and dominates all 10 of the CDC's regions. The late-season rise of influenza B is a typical pattern seen in the United States and elsewhere.
The rate of flu hospitalizations, however, climbed again, from 59.9 to 61.1 per 100,000 population. The rate of flu hospitalizations in people age 65 and older—the hardest hit group this flu season—rose again to an all-time record high, increasing from 296.2 to 301.8 per 100,000 population. That is the highest it has been since the CDC began tracking that figure that age-group in 2005.
For deaths, the overall percentage linked to pneumonia and flu tumbled from 6.9% to 6.5%, putting it below the seasonal baseline for this point in the flu season. Two more pediatric flu deaths were reported, which occurred in early March. Both involved influenza B. So far 125 children's flu deaths have been reported this flu season.
No states or territories reported high flu activity last week, and four reported widespread geographic flu circulation, the same as last week. All four are located in the Northeast.
Apr 10 CDC weekly FluView report
Apr 10 CDC flu situation report
CDC: Rotavirus vaccine drove steep decline in young kids' disease
The introduction of the rotavirus vaccine in 2006 in the United States not only drove steep declines in diarrhea and hospitalizations in young children, it also appears to have changed the seasonality and epidemiology of the disease, researchers from the Centers for Disease Control and Prevention (CDC) reported today.
They based their findings on a comparison of testing data from 2000 to 2006 before the vaccine was introduced with data from 2007 to 2014, after the vaccine's launch. The team published its findings in Morbidity and Mortality Weekly Report (MMWR).
Before the vaccine was available, the disease had a winter-spring seasonality and a geographic pattern marked by a wave that started in the western United States and spread to the East Coast as the season progressed. After the vaccine was available, however, a biennial pattern emerged, with years of low activity and erratic seasonality alternating with years of moderate activity with a timing pattern that mimicked the pre-vaccine years. Yearly disease declines in the years after vaccination began ranged from 57.8% to 89.9%.
Researchers said that the later, shorter seasons seen after the vaccine was introduced could be the result of fewer unvaccinated infants, which may have led to a herd immunity effect that benefited older unvaccinated kids and even some adults. They added that the biennial pattern in the post-vaccine era might be related to unvaccinated babies in a low rotavirus year being vulnerable to the virus in their second year of life, which could sustain more intense transmission in alternate years.
The group said their findings support other US studies showing declines in rotavirus hospitalizations, as well as reductions in other healthcare burdens, in the wake of vaccination. "Taken together, these findings reaffirm the large public health impact of routine rotavirus vaccination in reducing the circulation of rotavirus among US children," they wrote.
Apr 10 MMWR report
NIH awards $11 million for drug-resistant bacteria tests
In a response to President Barack Obama's recent national action plan to combat drug-resistant bacteria, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, has awarded more than $11 million in first-year funding for nine research projects for developing enhanced diagnostics to rapidly detect antimicrobial-resistant bacteria, the NIAID said in a news release yesterday.
The projects involve developing tools to identify pathogens that frequently cause infections in healthcare settings, especially those resistant to most antimicrobials.
NIAID Director Anthony S. Fauci, MD, said, "One way we can combat drug resistance is by developing enhanced diagnostic tests that rapidly identify the bacteria causing an infection and their susceptibility to various antimicrobials. This will help physicians determine the most effective treatments for infected individuals and thereby reduce the use of broad-spectrum antibiotics that can contribute to the drug resistance problem."
The awardees are: BioFire Diagnostics, LLC, Salt Lake City; Brigham Young University, Provo, Utah; Denver Health and Hospital Authority; First Light Biosciences, Inc., Bedford, Mass.; GeneFluidics, Inc., Irwindale, Calif.; Johns Hopkins University, Baltimore; The Broad Institute of MIT and Harvard, Cambridge, Mass.; the University of California, Berkeley; and the University of California, Irvine.
Apr 9 NIH news release