News Scan for May 21, 2019

Temperature-stable vaccines
Dengue on Reunion
Avian flu in Vietnam, Mexico

Method developed to store antiviral vaccines at high temperatures

It a development that has the potential to replace cold chain antiviral vaccine storage systems that make it difficult to immunize people in remote and low-resource regions of the world, researchers today described a stable, affordable system for storing fragile vaccines for weeks. Researchers based at McMaster University described their findings today in Scientific Reports.

The new system combines active vaccine ingredients with a sugary gel containing pullulan and trehalose that had already been developed by McMaster chemical engineers as an edible coating to prolong the shelf life of fruits and vegetables. The technique adds a marginal cost to preparing the vaccine, but eliminates nearly all the transport cost, which can make up 80% of the total cost of the vaccine.

The vaccine can be stored at temperatures as high as 104°F (40°C) for 8 weeks or more. The method stores the active component in a tiny one-dose container filled with the sugar-gel combination that seals the vaccine. When administering the vaccine, the clinician reconstitutes it with water as he or she normally would.

Ali Ashkar, DVM, PhD, study coauthor and professor of pathology and molecular medicine at McMaster said in a press release from the university, "You can spend all kinds of money developing a vaccine, but if it is deactivated by high temperature an hour before you can give it to someone, it doesn't matter."

The team successfully used the system on two sample vaccines using influenza and herpes simplex to inoculate mice. They note that the ingredients in the storage medium are already approved by the US Food and Drug Administration. The researchers are working with a commercial partner to bring the technology to market.
May 21 Sci Rep abstract
May 21 McMaster University press release


WHO: Spike of dengue activity in French territory, Reunion Island

The French territory of Reunion, an island east of Madagascar, has noted a sharp increase in dengue cases since early 2018, according to an update from the World Health Organization (WHO) yesterday.

"A total of 6,942 confirmed locally acquired cases of dengue fever were reported in Reunion in 2018, a 6,000% increase from 2017, when 100 cases were reported,"  the WHO said. Since Jan 1 of this year, officials have recorded more than 7,700 confirmed dengue cases. So far 14 deaths since 2018 have been linked to dengue infections, and emergency room visits rose from 475 in 2018 to 1,102 in 2019. 

Reunion's first dengue outbreak took place in 1977 and 1978, and officials estimate about 30% of the population has been infected with the virus.

The surge in new cases could be explained by either an increase in the viral load of asymptomatic cases over the threshold values of infectivity for mosquito vectors, or a lack of herd immunity in the local population for the prevailing serotypes. The WHO also said the co-circulation of different serotypes may also be contributing to transmission.
May 20 WHO update


Vietnam and Mexico report high-path avian flu outbreaks

In the latest highly pathogenic avian flu developments involving poultry, Vietnam reported an H5N1 outbreak in village birds and Mexico reported five more H7N3 outbreaks, mainly in backyard birds.

Vietnam's outbreak began on May 4 in a village in Hau Giang province in the far south of the country, according to a notification from the World Organization for Animal Health (OIE). The report didn't say how many birds died from the virus, but it noted that authorities culled 1,120 of them. The country reported its last H5N1 detection in March.

Mexico's five H7N3 outbreaks are part of sporadic detections involving the strain since early April. Four of the events were in backyard poultry in Queretaro, Guerrero, and Tlaxcala states, all in the south central part of the country. The fifth involved a commercial layer farm in Queretaro state.

The events began from Apr 24 to May 7 and are considered resolved. The virus killed 1,266 of 2,107 susceptible birds, and authorities destroyed the remaining ones as part of response steps.
May 20 OIE report on H5N1 in Vietnam
May 18 OIE report on H7N3 in Mexico

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