News Scan for Nov 15, 2017

Northern Hemisphere flu uptick
;
Flu vaccine protection by age
;
Madagascar plague declines

Flu increasing slightly in Northern Hemisphere

In its latest global flu update, the World Health Organization (WHO) notes that flu increased slightly in the Northern Hemisphere last week and globally influenza A H3N2 is still the dominant strain.

According to the WHO, respiratory illness indicators were at or below seasonal thresholds in Mexico and the United States, and following historical trends in Canada.

Flu activity is still low in general for North America, Central America, and Europe. Levels are also low for much of Asia and the Middle East. Qatar is one of the few places to report high flu activity, and influenza like illness and severe acute respiratory infection indicators appear to have increased in Kazakhstan, Tajikistan, and Uzbekistan in Central Asia.

In India and the temperate zone of the Southern Hemisphere, overall flu indicators are dropping.

Of flu samples collected and tested from Oct 16 to Oct 29, 72.3% were typed as influenza A and 27.7% as influenza B. Of the subtyped influenza A viruses, 13.8% were H1N1 and 86.2% were H3N2.
Nov 13 WHO report

 

Study finds low overall flu vaccine protection but higher in some groups

Israeli researchers found flu vaccine effectiveness of 29.0% against influenza H3N2 last season, when that strain caused 98% of infections, but protection was as high as 69.2% in some age-groups. The team reported its findings yesterday in Clinical Infectious Diseases.

The investigators analyzed data from 1,088 patients collected during the 2016-17 flu season; among 467 lab-confirmed isolates, 97.9% were the H3N2 strain. They estimated age-specific vaccine effectiveness (VE) using a moving age window of 15 years and weekly analysis.

The team found an overall flu VE of 29.0% against H3N2 flu, but among children age 5 to 17 years, it was 69.2%. Flu VE among those 45 to 64 was 58.8%. Other age-groups had low VE numbers that were not statistically significant.

The researchers conclude, "Estimating VE using a moving age window, and weekly VE analysis may provide more detailed information regarding the relationship between VE and age."
Nov 14 Clin Infect Dis study

 

WHO: Epidemic phase of Madagascar's plague outbreak winding down

In an update today on plague in Madagascar, the WHO said declines since the middle of October in new cases, hospitalizations, and affected districts suggest that the epidemic phase is ending. It added, however, that sustained efforts are critical for minimizing bubonic illnesses and human-to-human spread of the pneumonic form of the disease.

As of Nov 10, the total number of confirmed, probable, and suspected cases is 2,119, including 171 deaths, for a case-fatality rate of 8%. So far, 76% of the cases have been the potentially fatal pneumonic plague, an unusual feature in Madagascar, where the disease—primarily the bubonic form—is endemic, with a season that runs from September through April.

The WHO said that, as of today, only 12 patients are still hospitalized.

The last lab-confirmed bubonic case was reported on Oct 24, and the last confirmed pneumonic case was reported on Oct 28. In a situation report posted yesterday on the WHO African regional office website, officials said 86 cases were reported from Nov 7 to Nov 10, most of which appear to be probable and suspected.

The WHO said though recent downturns in outbreak markers are encouraging, it expects more cases to be reported until the end of the typical plague season. "It is therefore important that control measures continue through to the end of the plague season," it added.
Nov 15 WHO statement
Nov 14 WHO Regional Office for Africa situation report

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