News Scan for Jun 30, 2017

Flu vaccine in kids
;
PPE for Ebola
;
Powassan virus infection
;
Legionnaires' outbreak

Flu vaccine effectiveness study in kids finds modest, consistent benefit

A study in children tested for flu over three seasons at a New Orleans hospital found modest but consistent flu vaccine effectiveness, that a switch from the inactivated trivalent to quadrivalent (four-strain) formulation didn't seem to help or hurt effectiveness, and that the inhaled version of the vaccine didn't perform as well, but improved over successive seasons. Researchers from Louisiana State University published their findings yesterday in Vaccine.

Using the test-negative method for assessing flu vaccine effectiveness, the team evaluated 6,779 children over three seasons: 2013-14 when the trivalent vaccine was most commonly used in injectable vaccines and 2014-15 and 2015-16 during the transition to quadrivalent versions. Over the 3 years, 15.6% tested positive for flu, 77% of them for an influenza A virus. Overall, 27.2% of children had been vaccinated, 87.1% with one of the inactivated injectable vaccines and 12.9% with the quadrivalent inhaled live attenuated influenza vaccine (LAIV). The 2009 H1N1 virus was most common during the first and last seasons, and a drifted H3N2 strain was predominant during the middle season.

The effectiveness of injectable vaccines didn't vary much over the three seasons, measuring 60%, 57%, and 53%, respectively, and performing similarly against A and B strains in the kids younger than 5 and those ages 5 to17.

For the LAIV, effectiveness was poor against influenza A, but improved over the three seasons, measuring 15%, 37%, and 48%, respectively. That vaccine formulation performed much better against influenza B and in the older age-group.

The researchers said the efficacy they saw for LAIV for the latter two seasons they studied was higher than the US Centers for Disease Control and Prevention (CDC) estimates, which formed the basis of its advisory group's decision to pull its recommendation for the vaccine for the 2016-17 flu season. They said the difference between the CDC's findings and the results in New Orleans children emphasizes the regional nature of flu and usefulness of local surveillance to better understand the disease.
Jun 29 Vaccine abstract

 

Wet PPE allows more Ebola virus penetration than dry, study finds

A study yesterday in Scientific Reports found that water-saturated personal protective equipment (PPE) allowed Ebola virus to penetrate the material 33% of the time, compared with 5% for dry PPE. The study sought to explain how healthcare workers wearing PPE during West Africa's 2013-2016 Ebola outbreak contracted the deadly virus.

At the height of the West African Ebola outbreak, 12.3% of healthcare workers contracted the virus, so Canadian researchers recreated the environmental conditions, including humidity and temperature, to understand how the virus reacted to PPE, including Tyvek hoods, masks, and rubber boots, especially during hot, humid conditions that produce heavy perspiration.

The researchers found that the outbreak Ebola-Makona virus persisted on PPE and materials found in outbreak settings for less than 72 hours at 27°C and 80% relative humidity. Five percent of viruses sampled penetrated dry PPE, while 33% penetrated with saturated or damp PPE. Virus particles penetrated through surgical masks, Tyvek materials, and N95 respirators.

"Notably, virus persisted long enough (>24 hours) to allow for possible fomite driven transmission if contaminated surfaces are not properly identified and disinfected," the authors concluded, suggesting that saturation tests be used before PPE gear is manufactured for Ebola-treating health care workers.
Jun 29 Sci Rep study

 

Powassan virus detected among patients with suspected Lyme

A report yesterday in Emerging Infectious Diseases examined 95 Wisconsin patients who had suspected Lyme disease and 50 patients undergoing routine chemical screening. In both groups, clinicians found serologic evidence of Powassan virus infection, an emerging flavivirus spread by deer ticks—the same ticks that spread Lyme.

Nine (9.5%) of the 95 patients with suspected Lyme and 2 (4.0%) of the patients undergoing routine screening tested positive for Powassan, with infection occurring in 3 of them, but none having neurologic manifestation, according to the study conducted in the summer of 2015 at the Marshfield Clinic in northern Wisconsin.

Evidence of current or prior Borellia burgdorferi infection, the bacterium that causes Lyme disease, was present in 63 (66.3%) of the patients with suspected disease and 4 patients (8%) screened by chemical methods. Of the 41 (43.2%) patients with evidence of B burgdorferi infection, 7 (17.1%) had serologic evidence of acute Powassan infection and 3 (7.3%) had laboratory-confirmed Powassan infections.

The authors suggest that Powassan is more widespread in Lyme-endemic areas than previously thought.
Jun 29 Emerg Infect Dis study

 

Memphis officials confirm Legionnaires' disease at Graceland hotel

Health officials from Shelby County, Tennessee, have confirmed that three people have been diagnosed as having Legionnaires' disease after using the aquatic facilities at the Guest House at Graceland, a hotel near Elvis Presley's former home.

The local health department has suspended all use of the hotels pools and hot tubs, and urges recent guests to visit their doctor if they visited the hotel between May 15 and June 26 and develop symptoms of the lung infection.

Earlier this month, the CDC released new data on Legionnaires', showing that the Legionella bacterium is increasingly prevalent in American hospitals, hotels, and retirement homes. The bacteria thrive in buildings with outdated water systems.

If caught early, Legionnaires' can be treated with a course of antibiotics. In the elderly and the sick, the disease can cause severe pneumonia and even death. According to the CDC, about 5,000 people are diagnosed as having Legionnaires' disease annually, and the number has increased in recent years. There are at least 20 outbreaks reported each year.
Jun 29 Shelby County press release
Jun 6 CIDRAP News story "CDC: Most healthcare-acquired Legionnaires' cases could be prevented"

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