News Scan for Apr 18, 2019

News brief

Experts warn US is 'going backward' with measles

With the current resurgence of measles two decades after it was eliminated, the United States is going backward with measles, leading US experts are warning.

The commentary, by Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases of the National Institutes of Health along with other public health leaders, appeared yesterday in the New England Journal of Medicine. US officials have confirmed 555 measles cases so far in 2019, and the country is on pace to soon pass 2014 totals to reach the most cases since the disease was declared eliminated in 2000.

The experts explain that measles is highly contagious—90% of people who are not immune will contract the disease if exposed. And though most suffer a mild week-long illness, a significant proportion of cases are fatal. Measles is the leading cause of vaccine-preventable illness and death around the globe, with 100,000 cases attributed to the virus annually—but this year has already topped that number globally.

Because measles is so contagious, herd immunity, which is achieved by 93% to 95% coverage, must be reached to stop transmission. Nearly complete protection is entirely attainable given the highly effective measles, mumps, and rubella vaccine.

"Unlike many infectious diseases, measles is a public health problem with a clear scientific solution," Fauci said. But resistance to vaccination has resulted in a 31% increase in the number of measles cases reported globally between 2016 and 2017—and the rise will be even greater this year.

Fauci and colleagues said, "If this trend is not reversed, measles may rebound in full force in both the United States and other countries and regions where it had been eliminated." They add that promoting measles vaccine is a societal obligation.
Apr 17 N Engl J Med commentary

 

Study: Rates of high-grade cervical lesions decline after HPV vaccination

Researchers today in Morbidity and Mortality Weekly Reports (MMWR) published the first-ever estimate of cervical precancers using population data of US women. From 2006 through 2018, detection rates of high-grade cervical lesions (CIN2+, with CIN referring to cervical intraepithelial neoplasia) declined from 216,000 cases to 196,000, largely attributed to the use of the human papillomavirus (HPV) vaccine, they write.

The decline was seen in women ages 18 to 24, and 76% of cases were attributable to nine-valent (nine-strain) HPV vaccine types. CIN2+ lesions are the most concerning and can lead to cervical cancer, and scientists use CIN2+ rates to monitor vaccine impact.

In 2006 the HPV vaccine was licensed for use in women up the age of 26. Women ages 40 to 64 saw significant increased rates of CIN2+ during the study period than did younger cohorts, who were likely vaccinated with one of two HPV vaccines available for use. In 2016, coverage of more than one dose was 65.1%, and the recommended three-dose coverage was 43.0% for girls ages 13 through 17, the authors said.

"In younger age groups, the decline in HPV 16/18-attributable CIN2+, targeted by the quadrivalent vaccine from 2006 to 2015, also reflects the impact of the U.S. HPV vaccination program," the authors said. "Some of the increases in older age groups could be attributable to use of HPV testing, which is more sensitive than cytology, as part of cervical cancer screening, as has been predicted by modeling studies."
Apr 19 MMWR
study

 

Cambodia reports first H5N6 outbreak; other strains hit birds in 3 countries

Cambodia's agriculture ministry today reported the country's first detection of highly pathogenic H5N6 avian flu in poultry, and three other countries—Bangladesh, Mexico, and Taiwan—recorded events involving other strains, according to the latest notifications from the World Organization for Animal Health (OIE).

In Cambodia, testing in late March as part of active surveillance found H5N6 in poultry at a live-bird market in Takeo province. Ten of 100 birds tested positive, and the remaining ones were culled to curb the spread of the virus. Other Asian nations have also reported H5N6 in poultry, including China, Laos, Hong Kong, Vietnam, Japan, South Korea, Myanmar, and Taiwan. H5N6 has also been linked to a limited number of human infections, though so far only in China.

Elsewhere, Bangladesh said tests on house crows found dead in Khulna division in the country's southwest tested positive for an H5 strain. The report didn't specify the subtype. The outbreak began on Dec 15, involved 31 birds, and is now considered resolved.

In developments involving other strains, Mexico's agriculture ministry reported three H7N3 outbreaks in backyard poultry, two in Jalisco state and one in Mexico state, both in the south central part of the country. The events began on Apr 9, killing 750 of 2,527 susceptible birds collectively. Earlier this month Mexico reported another H7N3 outbreak in backyard poultry in Mexico state.

And finally, Taiwan reported two more H5N2 outbreaks, both at poultry slaughterhouses detected during postmortem testing. The outbreaks began on Mar 24 and Mar 26 and are now considered resolved. Taiwan has reported dozens of outbreaks of H5N2 in commercial poultry since 2015.
Apr 18 OIE report on H5N6 in Cambodia
Apr 17 OIE report on H5 in Bangladesh
Apr 17 OIE report on H7N3 in Mexico
Apr 17 OIE report on H5N2 in Taiwan

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