WHO weighs lower dose amid yellow fever vaccine shortage


While many in the world are focusing on the headline-grabbing Zika outbreak, another mosquito-borne disease has left hundreds dead in Angola. Responding to a global vaccine shortage and the threat of further spread, WHO officials are now working up a plan that would allow local authorities to drastically lower vaccine doses to extend supplies.

Since the outbreak began in late 2015, WHO reports that yellow fever has claimed 328 lives in Angola and has spread to other countries in Africa and South America as well as China, which has Angolan ties. With vaccine supplies nearly depleted following a campaign to immunize the millions of residents in Angola’s capital of Luanda, experts are searching for solutions in the event of a further spread, Reuters reports.

WHO’s officials are weighing a strategy that would allow a one-fifth dose on an emergency basis, the news service said, and could recommend the tactic to local authorities combating the outbreak. This comes as local transmission has been reported in Kinshasa, the Democratic Republic of Congo capital with a population of more than 10 million.

The need to vaccinate Kinshasa could serve as a “trigger” for the low-dose strategy, WHO vaccine expert Alejandro Costa told Reuters, adding “we don’t have enough vaccine.” In a yellow fever strategy report issued this week, WHO said it plans to “validate and adopt dose-sparing strategies to increase vaccine availability,” among many other tactics.

As of an April recommendation to pursue the strategy by outside experts, the world’s yellow fever vaccine capacity is about 80 million doses per year, but the supply is only at about 5 million doses, the group said. In a Lancet article suggesting WHO consider the move, the authors pointed to research finding that a lower dose is as effective in rapidly stimulating immunity.

Still, doubts linger over the length of immunity and whether the strategy could protect children.

According to WHO listings, Sanofi Pasteur, the Institut Pasteur Foundation in Dakar, Brazil’s Bio-Manguinhos/Fiocruz and a state-owned manufacturer are makers of yellow fever vaccines.  The Institut Pasteur Foundation in Dakar has plans to build a new yellow fever vaccine plant in that country, but the facility isn’t expected to be ready until 2019.

The yellow fever virus is spread by the same mosquitos that transmit Zika and dengue and can kill at least half of severely affected patients who don’t receive treatment in 10 to 14 days.

- here's the Reuters piece
- and the WHO strategy

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Yellow fever vaccine shortage prompts call for a lower dose