#7624
Although we’ve seen very little in the way of H7N9 activity from China over the past three months, fall is not far off and there are legitimate concerns that another outbreak may be only weeks or months away.
The United States has committed millions of dollars towards the development of an H7N9 vaccine (see Helen Branswell’s Can a usable H7N9 vaccine be made? Pending research should offer clues soon), and last month Xinhua News reported that China’s Sinovac Biotech Ltd. was engaged in preliminary safety testing of a vaccine.
Japan, which has historically taken the pandemic influenza threat very seriously (see H7N9: Japan Prepares A Public Health Response), today announced their intention to go ahead with the production, and appropriate testing, of their own H7N9 vaccine.
This from The Mainichi.
Gov't eyes vaccine for H7N9 bird flu before virus mutates
September 02, 2013(Mainichi Japan)
The government has decided to collaborate with a manufacturer in developing a vaccine for the deadly H7N9 strain of bird flu that has spread in China, before the virus mutates into a form that could easily spread among humans.
The Ministry of Health, Labor and Welfare will have the company produce a small batch, aiming to test the vaccine on animals from the beginning of next year. It will make preparations to begin production from as early as next fiscal year.
While researchers are hopeful that a safe, immunogenic H7N9 vaccine can be created, as we saw last May in JAMA: Challenges Of Producing An Effective & Timely H7N9 Vaccine, the track record for producing avian flu vaccines has not been good.
Earlier H5 and H7 experimental vaccines have required unusually large amounts of antigen (up to 12x normal) to induce a good immune response, a specification that would greatly reduce the number of shots that could be produced each year.
Adjuvants - additives often used in European flu vaccines to increase their immune response – could be used to help `stretch’ the vaccine supply.
But adjuvants have never been used in the U.S. flu vaccines, would require an EUA (Emergency Use Authorization), and might induce reluctance in some people to take the vaccine.
Once a vaccine can be developed, tested (first on animals, then humans), and mass produced there will still remain difficult decisions on vaccine prioritization, and global distribution.
If, as expected, it will require 2 shots - 4 weeks apart - to confer a reasonable level of immunity, the logistics of delivering the vaccine grow even greater.
Which means that - should the H7N9 virus take off this fall or winter – vaccines are not going to be widely available to the general public.
Instead, we will be looking to measures like social distancing, school closures, hand hygiene & masks (aka Nonpharmaceutical Interventions NPIs) along with neuraminidase (NA) inhibiting antiviral drugs (NAIs) like oseltamivir (Tamiflu ®) and Zanamivir (Relenza ®) to help mitigate its impact.
Should the H7N9 virus, novel coronavirus, or any other novel virus threaten, we’ll be talking a lot about NPIs, and their efficacy, impact, and practicality in the blog.
Granted, H7N9 may never pose a pandemic threat.
We’ve seen other flu viruses threaten (H5N1, H7N7, H9N2, 1976 H1N1, etc.), but fail (so far, at least) to produce a global health emergency.
But as we’ve seen four times in the last century (2009, 1968, 1957 and 1918) – pandemics do happen. Which is why governments around the world are taking this H7N9 threat seriously.
