Monday, November 13, 2017

China: Guangdong Province Reports 97% H7N9 Vaccine Coverage
















#12,895


Guangdong Province, which was the first to report the discovery of a new HPAI version of H7N9 last January, was one of two provinces selected last June to test a new combination H5+H7 poultry vaccine last summer (see China To Test New H7N9 Poultry Vaccine In Two Provinces).
While meant to be a pilot program to determine its effectiveness, within a month the go ahead was given to expand the project (see China MOA Orders HPAI H7N9 Vaccine Deployed Nationwide This Fall) as reports of HPAI H7N9 outbreaks continued to pour in. 
As we discussed six weeks ago in J. Virology: Genesis and Spread of Newly Emerged HPAI H7N9 In China, this new HPAI H7 virus not only appears to pose a greater threat to human health than its LPAI predecessor, but it may also be spreading more efficiently via migratory birds. 

As the the world's largest user of poultry vaccines, China has managed to save tens of millions of birds from being culled over the past 12 years, but at a price. As we’ve discussed often (see  MPR: Poultry AI Vaccines Are Not A `Cure-all’ & The HPAI Poultry Vaccine Dilemma), despite more than a dozen years of of heavy use, poultry AI vaccines have proven to be less than a panacea for bird flu. 

They may suppress bird flu, but they don't always eliminate it.  The countries that went with vaccination in 2005-2006 continue to be plagued by outbreaks.
The problem is that as avian viruses evolve, poultry vaccines become increasingly less effective; often only masking the symptoms of infection. Poor vaccine matches can allow AI viruses to spread silently among flocks, to continue to reassort and evolve, and potentially lead to the emergence new subtypes of avian flu. A few earlier blogs on that include:
Subclinical Highly Pathogenic Avian Influenza Virus Infection among Vaccinated Chickens, China).

Study: Recombinant H5N2 Avian Influenza Virus Strains In Vaccinated Chickens

EID Journal: Subclinical HPAI In Vaccinated Poultry – China
 
For these reasons, most of the rest of the world eschews the use of poultry AI vaccines, and instead follows the OIE recommendations to quarantine and cull infected birds (see South Africa Rejects Vaccination to Control Bird Flu).

A handful of countries - notably China, Egypt, Vietnam, and Indonesia - which have serious food insecurity issues, have opted instead to rely on AI vaccines to control bird flu.
Today Chinese media are carrying reports from Guangdong's Ministry of Agriculture that claim they've reached a 97.87% vaccination coverage in poultry.  While an impressive number, it remains to be seen just how effective this vaccine is in actual practice  . . . and for how long it remains protective.

This (translated) report from the Gaungzhou Daily. 

Provincial Agriculture Department responded "voice of the people Ten Questions"

97% of poultry vaccines to fight H7N9

Tom South

  Guangzhou Daily News (all media reporter Tom Southern correspondent Lai Haofeng) Guangdong prevention of H7N9 bird flu outbreaks have any new method; the farmers accounts to move out, whether contracted to do the right; how to prevent "Situlanzai" phenomenon; buy "imported pet food, "how to tell whether a formal legal source ...... yesterday, the Guangdong Provincial Department of agriculture responded to Guangdong" voice of the people hotline "collection" ten Questions voice of the people. "

  There are new ways to prevent bird flu

  December to March each year of the period, people are infected with bird flu high time, what new means of prevention methods in Guangdong this year there?

  Provincial Agriculture Department official said in July this year, Guangdong was the first nationwide H7N9 immunization pilot, as of now, the province has organized around 174 million ml vaccine made to carry out immunization, the immunization of nearly 276 million poultry, poultry shall be exempt about 282 million poultry herd immunity density reached 97.87 percent, and build a solid immune barrier.

  "From the current point of view the results of monitoring and evaluation, H7 vaccine works well, antibody levels can reach more than 70%, can effectively protect poultry." The official said Guangdong will adhere to the "central slaughtering, fresh on the market."
(Continue . . . )
During the 5th epidemic wave, in addition to battling outbreaks in poultry, Guangdong Province reported 63 human infections (both from LPAI and HPAI H7N9), bringing their 5 season total to 258.

Between Guangdong's proximity to - and close economic ties with - Hong Kong, and recent reports suggesting that HPAI H7N9 may be becoming more transmissible (see Cell Host & Microbe: HPAI H7N9 Lethality & Transmission In Ferrets), the need to effectively control China's H7N9 epidemic has never been greater.
China's gamble is that their new H7N9 vaccine can effectively prevent H7N9 in poultry, without promoting the creation of new `vaccine escape' viruses. For the world's sake, we need to hope they get it right.
While we may get some indication about the first half of that equation this winter, the longer-term impacts may take more time before they become apparent. 

Stay tuned.

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