Judging by the headlines coming out of China the past few days, one could be forgiven for believing that China was on the verge of producing, and deploying, a massive quantity of H7N9 vaccine to its people.
It’s a reassuring, but somewhat dubious claim, considering that the US isn’t scheduled to complete their vaccine clinical trials until late in the year (see NIH Begins Phase II Clinical Trials On H7N9 Vaccine Candidates.)
Last Friday, we saw this from Xinhua News:
BEIJING, March 7 (Xinhua) -- Vaccines for H7N9 bird flu could hit the market as early as May, a Chinese expert on infectious disease said Friday.
The vaccine is currently being submitted to drug control authorities for tests, said Li Lanjuan, an academician with the Chinese Academy of Engineering.
"If everything goes smoothly, we could have the vaccine on the market within one to two months," said Li, who is also a member of the Chinese People's Political Consultative Conference National Committee.
While yesterday, the similarly upbeat assessment was:
Global Times | 2014-3-11 0:53:01
By Global Times
China has prepared the H7N9 vaccine seeds for mass production in case human-to-human transmission occurs, a deputy to the National People's Congress (NPC) said Monday.
China has manufactured some vaccine products and they could be used on high-risk groups, Zhong Nanshan, NPC deputy and member of the Chinese Academy of Engineering, said at a press conference at the annual parliamentary session.
As is often the case, particularly when we talk about experimental vaccine production, the devil is in the details. There’s good reason to believe that China isn’t quite as close `mass production’ of an H7N9 vaccine as these stories might suggest, for we’ve another report today indicating that this `seed vaccine’ has only just completed `pre-clinical studies’ .
World-renowned infectious disease expert Yuen Kwok-yung said the vaccine will not be a large-scale investment by temporarily
Shenzhen Special Zone Daily (Reporter Sheng Jiawan) At present, people infected with H7N9 bird flu has risen to 354 cases, Guangdong Province, recently there have been new cases still occur. How H7N9 vaccine development situation? When the virus will disappear? Prevention and control of H7N9 avian influenza in Hong Kong can be learn what experience? Yesterday, the reporter interviewed the world-renowned infectious disease experts, the Chinese Academy of Engineering Yuen Kwok-yung.
Vaccine production temporarily not
Q: H7N9 vaccine developed to what stage?
A: Currently, pre-clinical studies have been completed. In the experimental mouse model, the effectiveness of the vaccine has been initially confirmed. Theoretically, then after about 200 cases of clinical trials, to be put into use.
In other words, it appears that China has yet to seriously begin the human testing phases for this vaccine, a process that could take many months and could run into challenges along the way. So the claim last Friday that this vaccine may `Hit the Market in May’, would seem more than just a little ambitious.
Although selection of a `seed strain’ and pre-clinical (animal) testing is a critical part of the vaccine development process, clinical data must also be gathered over (normally) three phases of human testing.
- Initially (Phase I) a small number of test subjects are immunized to test the vaccine’s safety, and immune response.
- Larger human trials (Phase II) are then undertaken to gain additional safety information and compare dose ranges (with and without adjuvants)
- And finally, a much larger scale human trial (Phase III) is undertaken to determine the safety, immunogenicity, and efficacy of the vaccine.
While a sudden dramatic change in the virus’s behavior might prompt some to call for shortcuts in these testing procedures, there is absolutely no reason to risk that right now when the virus is only sporadically jumping to humans.
Sentiments echoed by Professor Yuen Kwok-Yung of Hong Kong’s University at a press conference today.
2014-03-12 14:25 Ecns.cn Web Editor: Si Huan
(ECNS) – It's not necessary for China to promote the H7N9 flu vaccine on a large scale at this time, an expert at Hong Kong University said on Tuesday, according to Caixin.com.
Yuen Kwok-Yung, chief of the State Key Laboratory for Emerging Infectious Diseases, made the statement at a press conference at Shenzhen Hospital affiliated with Hong Kong University.
So far, H7N9 is transmitted from a first-infected person to a second, but transmission from a second-infected person to a third one hasn't occurred yet, he said.
"Only when confirmed cases surge in a short period or when person-to-person transmission becomes worse should China promote the vaccine extensively across the country," Yuen added.
Vaccine strains for H7N9 avian flu were developed jointly by Zhejiang University and Hong Kong University last October.
As a member of the development team, Yuen said a H7N9 vaccine has been undergoing clinical trials, but its safety is not yet confirmed.
While work is being done on an H7N9 vaccine in China, Taiwan, Japan, and the United States - and there are hopes that a practical one can be created – there are a great many issues that must be sorted out first, including:
- The correct amount of antigen needed to achieve an adequate immune response
- The timing or need for a booster shot
- The incidence and severity of side effects
- Determining whether an adjuvant is needed
And then there’s several months of vaccine production, fill and finish, shipping, and local distribution to take into account.
Realistically, all of which means we are still a long way from having any quantity of commercial H7N9 vaccine available to the public.
For more on the challenges H7N9 vaccine development, you may wish to revisit: