News Scan for Jul 29, 2019

More US measles cases
;
H7N3 in Mexican poultry
;
Tamiflu in low-risk groups

US measles total grows by 16 cases, to 1,164 total

Sixteen more measles cases were reported to the US Centers for Disease Control and Prevention (CDC) last week, lifting the total for 2019 to 1,164. The number of affected states held steady at 30, according to the CDC's regular weekly update today.

The number of weekly cases is down a bit from the 25 cases reported in the previous week. The agency is still monitoring five outbreaks of three more related cases, which include two separate ones in New York (Brooklyn and Rockland County); one in Washington state; one in El Paso, Texas; and one in Los Angeles County, California.

In New York's Rockland County, health officials on Jul 25 announced the end of a measles emergency, an event that lasted 122 days. In a statement, the department said the number of new cases has decreased steadily since May and that vaccination numbers have climbed, with 25,876 given since October 2018. In its latest measles outbreak update, officials reported 284 confirmed cases, reflecting 2 more illnesses compared with the previous week.

Meanwhile, health officials in New York City reported 637 confirmed cases as of Jul 22, an increase of 14 since its last update. No new cases have been reported in an outbreak that began in May affecting three Washington state counties, and Los Angeles County has reported 2 more cases, bringing its outbreak total to 18, of which 5 are part of a second outbreak in the region that is still ongoing. And finally, 1 more case has been reported in an outbreak in El Paso, bringing the total to 6, according to a Jul 24 update.

The number of measles cases reported this year is the highest since 1992 and since the disease was declared eliminated in 2000, according to the CDC.
Jul 29 CDC update
Jul 25 Rockland County measles emergency step-down
Jul 26 Rockland County update
Jul 22 NYC Health update
Jul 24 California Department of Public Health measles update
Jul 24 El Paso Department of Public Health update

 

H7N3 avian flu strikes more poultry in Mexico

Animal health officials in Mexico have reported four more outbreaks of highly pathogenic H7N3 avian flu in poultry, according to a Jul 27 notification from the World Organization for Animal Health (OIE). Two of the outbreaks occurred at farms in Queretaro state in central Mexico, one was in backyard birds in neighboring Guanajuato state, and one involved backyard poultry in Veracruz state on the country's eastern coast.

The events began from Jun 29 to Jul 10, killing 4,282 of 195,852 susceptible birds. In all but one of the outbreaks, the virus was detected following deaths and clinical signs in birds. The third detection was part of epidemiologic surveillance in healthy birds at a fattening farm.

Authorities culled 17,369 poultry as part of the response to the outbreaks, which are part of sporadic detections of the virus in Mexico since April.
Jul 27 OIE report on H7N3 in Mexico

 

Study finds minimal Tamiflu impact in low-risk groups

A study on the impact of oseltamivir (Tamiflu) in adults at low risk for flu complications found that the medication decreased viral shedding at day 3, but did not significantly shorten the time until clinical symptom resolution.

The multicenter randomized, double-blind study included adults ages 18 to 64 years old at 42 clinical centers in Thailand, the United States, and Argentina from January 2012 to October 2017. An international research team published its findings Jul 27 in Clinical Infectious Diseases.

Of 716 adults screened for flu, 558 were randomized, and 501 were confirmed to have the virus. Participants were randomized to receive either 75 milligrams of oseltamivir or placebo twice daily for 5 days. The main goal of the study was to gauge detectable virus by nasopharyngeal swab sampling at day 3, and results were available for 449 of 455 people in the primary analysis group.

Of 220 subjects in the oseltamivir group, 99 of 220 (45%) had detectable virus at day 3, compared with 131 of 229 (57.2%) in the placebo group, for an absolute difference of -12.2. Meanwhile, the median time to symptom resolution was 79 hours for the oseltamivir group and 84 hours for the placebo arm, a difference that was nonsignificant (P = 0.34).

The authors said their study didn't show the same clinical benefits for low-risk patients as earlier licensing trials, but they said their results were consistent with findings from a Cochrane meta-analysis, which found considerable variation. They pointed out that their study population was different than earlier licensure studies, including that a much greater percentage of patients in the new study had been sick with influenza B. They said that the efficacy of the drug against influenza B has been questionable, and their data show little or no clinical or virologic efficacy against the influenza B in low-risk groups. The team also said their study enrolled patients from a broader group than earlier licensing trials, which focused on American and European participants.

They said, however, that their study should be used to question the drug's use in most populations, with many studies supporting clinical benefits with treatment recommendations justified for those who are very sick or who are at high risk for complications. They added that the minimal benefits they found should raise a caution about automatically extending treatment recommendations to low-risk groups.
Jul 27 Clin Infect Dis abstract

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