News Scan for Jun 13, 2018

Plague case in Idaho
;
Tamiflu and nursing home outbreaks
;
Vaccine exemptions in US

Idaho announces first plague case since 1992

A child from Elmore County, Idaho, is recovering from plague, the first human case confirmed in that state since 1992.

The Idaho Department of Health and Welfare (IDHW) said yesterday it is not known if the child contracted plague in Idaho or during a recent visit to Oregon. Both states have reported plague in wildlife.   

"The case serves as a reminder to recreationists in southern Idaho that plague is dangerous to people and pets, but with proper awareness, precautions, and prompt treatment when needed, plague should not discourage you from enjoying the Idaho outdoors," the IDHW said. Idaho state officials last confirmed plague in ground squirrels in the desert south of Interstate 84 in Ada County in 2015 and 2016.

Squirrels and other rodents can carry plague, which is often transmitted to humans via flea bites.  Humans can also contract Yersinia pestis, the bacterium that causes plague, after contact with an infected animal. In humans, plague can bring on a sudden onset of flu-like symptoms and painful swelling of the lymph nodes.

The new case is Idaho's sixth since 1940.
Jun 12 IDHW blog post

 

Study: Quick use of Tamiflu lowers odds of secondary infections

A new retrospective cohort study conducted in long-term care facilities (LTCFs) in Manitoba suggests that using oseltamivir (Tamiflu) as soon as possible after the start of an H3N2 flu outbreak can help reduce the risk of secondary infections.

The study was conducted during the 2014-15 flu season, during which there were 94 H3N2 outbreaks in Manitoba's LTCFs. Fifty-three outbreaks were included in the study.

In Manitoba, the standard protocol for an influenza outbreak in an LTCF is a 5-day course of oseltamivir at the therapeutic dose for symptomatic patients, with all other residents receiving 10 days of oseltamivir at a prophylactic dose. Researchers measured how many days passed between the start of the outbreak and the beginning of oseltamivir chemoprophylaxis.

Researchers found that for every day that passed from the start of an H3N2 flu outbreak to the initiation of oseltamivir in non-symptomatic residents, the odds of an at-risk resident developing a symptomatic infection increased by 33% (adjusted odds ratio, 1.3; 95% confidence interval, 1.21–1.5).

"This study provides strong evidence supporting the rapid detection of influenza A H3N2 outbreaks and the rapid administration of oseltamivir chemoprophylaxis in a LTC resident population," the authors concluded.
Jun 12 Infect Control Hosp Epidemiol study

 

Non-medical vaccine exemptions rising in states that allow them

Eighteen states allow non-medical exemptions (NMEs) from childhood vaccines, and a study published yesterday in PLoS Medicine shows that NMEs correlate with decreasing childhood vaccine uptake in certain cities and communities.

Researchers from Baylor College analyzed NME from the 2009-10 school year through 2016-17. In general, the number of NMEs increased from 2009 to 2014. Idaho had the highest NME rates in the country, with a handful of counties around or above a 20% exemption level.

Though most of the communities with high rates of NMEs were rural and home to fewer than 50,000 people, the researchers identified several major metropolitan areas with high NME status, including Phoenix, Salt Lake City, and Houston.

"The high numbers of NMEs in these densely populated urban centers suggest that outbreaks of vaccine-preventable diseases could either originate from or spread rapidly throughout these populations of unimmunized, unprotected children," the authors write.

The authors also included in their analysis a comparison between measles, mumps, rubella (MMR) vaccine rates and NMEs, showing an inverse association between NME rate and MMR vaccine coverage of kindergarteners (P = 0.03 by Spearman correlation).
Jun 12 PLoS Med
study  

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