News Scan for Mar 22, 2017

News brief

Study finds heat-stable rotavirus vaccine effective in preschoolers in Niger

An inexpensive heat-stable rotavirus vaccine was shown to be 67% effective in a resource-poor setting in Africa, providing renewed hope for addressing the deadly diarrhea-causing disease in children, a study today in the New England Journal of Medicine reported.

Rotavirus is responsible each year for about 37% of deaths from diarrhea in children younger than 5 years old globally, or about 450,000 children, with a disproportionate high number in sub-Saharan Africa. Two rotavirus vaccines were approved for use by the World Health Organization in 2008, but they require cold storage and have proved rather expensive—about $4.50 to $10.50 per dose.

The authors of today's study used a live, oral pentavalent (five-strain) rotavirus vaccine, called BRV-PV and made by the Serum Institute of India. The vaccine is thermostable for 24 months at 98.6°F (37°C) and for 6 months at 104°F (40°C), which could prove helpful in remote areas where cold-chain storage is limited. BRV-PV costs $2.50 per dose, according to a Doctors Without Borders (MSF) news release on the study.

In today's study, researchers from Harvard University and Epicentre, MSF's research center in Paris, included 3,508 healthy infants in Niger who received three doses of BRV-PV or a placebo at 6, 10, and 14 weeks of age.

The authors reported 31 cases of severe rotavirus gastroenteritis in the vaccine group and 87 in the placebo group, for a vaccine efficacy of 66.7% (95% confidence interval, 49.9% to 77.9%). Adverse events between the two groups did not differ significantly, and there were 27 deaths in the vaccine group and 22 in the placebo group. None of the infants had confirmed intussusception, a telescoping of the intestine that has been associated with rotavirus vaccines.

"This trial brings a vaccine which is adapted to African settings to those who need it most," said first author Sheila Isanaka, ScD, assistant professor of nutrition at Harvard's T.H. Chan School of Public Health, in a Harvard news release. "When the vaccine becomes widely available in Africa, it will help protect millions of the most vulnerable children." MSF Medical Director Micaela Serafini, MD, MPH, in the MSF release, called the vaccine a "game-changer."

In an accompanying editorial, Mathuram Santosham, MD, MPH, of Johns Hopkins, and Duncan Steele, PhD, of the Bill and Melinda Gates Foundation, write that the 67% efficacy is similar to that of other rotavirus vaccines in similar settings. They add, "Despite this modest efficacy, the absolute public health benefits of vaccination are large, given the tremendous disease burden."

The vaccine is also being tested in India.
Mar 22 N Engl J Med study
Mar 22 N Engl J Med editorial
Mar 22 MSF news release
Mar 22 Harvard news release


Study: South America Zika attack rates lower than in French Polynesia

A study yesterday in Scientific Reports found that attack rates of Zika varied from 78% in French Polynesia to 21% in Colombia and 32% in the state of Bahia, Brazil.

In this comparison study, researchers contrasted numbers from the 2013-14 French Polynesia outbreak with data collected 1 year after the current Zika outbreak began in Colombia and Brazil. For all three locations, Zika infection rates reached their peak within the first 6 months of disease detection, and the first wave of the disease was underreported.

Using a mathematical model, the researchers estimated a 78% attack rate in French Polynesia, among children ages 6 to 16. The rates were significantly less in Colombia and Brazil, despite research suggesting that the outbreaks in those countries came from the same strain of Zika seen in French Polynesia.

"The low attack rate in Colombia implies that parts of population were not infected during the 2015-16 ZIKV outbreak, hence a second wave of the epidemic could sweep the country," the authors write. "The lower attack rate in Colombia could partly be due to higher altitude and cooler weather than the other places."
Mar 21 Sci Rep study


USDA steps up Brazilian beef inspections over scandal allegations

In the wake of Brazilian police allegations that several of the country's meat producers bribed inspectors to allow the sale of rotten and Salmonella-contaminated meat, the US Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) said today it is taking extra steps to protect the US food supply.

The FSIS said though none of the facilities identified in Brazil's scandal have shipped meat products to the United States, it immediately instituted extra pathogen tests for all shipments of raw beef and ready-to-eat products from Brazil. The FSIS has also increased examination of all of the products at ports of entry. "The agency will indefinitely maintain its 100% reinspection and pathogen testing of all lots of FSIS-regulated products imported from Brazil." The statement noted that re-inspection of all Brazilian beef took effect on Mar 18.

Mike Young, the USDA's acting deputy secretary, said, "FSIS has strengthened the existing safeguards that protect the American food supply as a precaution and is monitoring the Brazilian government's investigation closely."

On Mar 17, Brazilian police released the results of a 2-year investigation that implicated two major companies, BRF SA (the world's largest poultry producer), JBS SA (the world's biggest meat producer), and dozens of smaller meatpackers, Reuters reported today. The findings allege that meatpackers paid off inspectors to overlook processing of rotten meat and shipping of exports with traces of Salmonella, as well as to not inspect plants. The companies have denied wrongdoing, and authorities have said no illnesses or deaths have been reported.
Mar 22 USDA press release
Mar 22 Reuters story

Avian Flu Scan for Mar 22, 2017

News brief

H5N1 strikes again in Vietnam as European countries report more H5N8

Vietnam today reported another highly pathogenic H5N1 avian flu outbreak, as two European countries—Romania and Slovenia—reported several more H5N8 outbreaks in wild birds and poultry, according to the latest updates from the World Organization for Animal Health (OIE).

In Vietnam, the new H5N1 event began on Mar 15 in backyard poultry in Can Tho province in the southern part of the country. The virus killed 396 of 794 susceptible birds, and authorities culled the remaining ones as part of the outbreak response. Since the first of the year, Vietnam has reported several H5N1 outbreaks and is also battling H5N6.

Elsewhere, Romanian veterinary officials reported 19 more H5N8 outbreaks, 17 in backyard poultry and 2 involving wild birds. Most were reported from Teleorman County in the south, with other locations including Bucharest, the country's capital, and Constanta County. The outbreaks began from Feb 23 to Mar 17, killing 167 of 501 poultry, plus 4 wild birds.

Slovenia reported 10 more outbreaks involving 253 wild birds—all but 3 were mute swans— found dead from Jan 26 to Feb 17 in four municipalities.
Mar 22 OIE report on H5N1 in Vietnam
Mar 21 OIE report on H5N8 in Romania
Mar 22 OIE report on H5N8 in Slovenia

H7N9 mutation noted that could affect ability to infect poultry, people

A research team from Hong Kong University (HKU) yesterday described a mutation in an H7N9 virus isolated in China that gives the virus the capacity to infect humans while circulating in poultry. They reported their findings in Nature Communications.

After analyzing the genome of a 2013 H7N9 virus, they identified unique NS-G540A substitution that it inherited from the H9N2 virus that provided the internal genes for H7N9. For H7N9, the mutation enhanced replication in mammalian cells and mice, while retaining the ability to replicate in avian cells.

They note that the endemic nature of H7N9 and persistent reemergence in humans is unusual, but add that their findings provide a possible mechanism to explain the pattern.

Chen Honglin, PhD, corresponding author and professor at State Key Laboratory for Emerging Infectious Diseases at HKU, said in an HKU news release that the mutation could provide an important biomarker for monitoring the emergence and transmission of avian flu viruses in humans and preventing human-to-human infection. "The mutation can also serve as a novel target of anti-influenza drug development," he said.
Mar 21 Nat Commun abstract
Mar 22 HKU news release

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