Re: Chin Sci Bull. Epidemiological and risk analysis of the H7N9 subtype influenza outbreak in China at its early stage
hat tip Crof
May 01, 2013
H7N9: From the authors of the CSB risk analysis
The
risk analysis published in
Chinese Science Bulletin is so far the most detailed we have, and I've commented on it
here and
here. The article drew criticism and speculation—criticism about its methods, and speculation about the political implications of its publication in China.
Rather than engage in further speculation, I emailed the corresponding author of the article, Professor Ji-Ming Chen, in Qingdao. I promptly received a long reply, which he has kindly given me permission to publish here. I have re-paragraphed for easier online reading, and corrected some minor English errors.
Dear Mr. Kilian,
Thank you for making some comments on our H7N9 paper published in
Chinese Science Bulletin in your blogs. I am interested in the fact from your blog that you have been an English teacher in China in the 1980s, and you run a big web blog on infectious diseases.
However, I have to clarify something about the paper, of which, I am the correspondence author.
First of all, the paper, like most other papers published in the world, represents only the views of the authors. It does not represent any view of any entities on any issues.
Actually, I was quite scared when I knew at the end of this March, that four cases from two provinces and one city, was infected with the H7N9 virus, and they had died or were in severe conditions. Why I was quite scared? Due to three reasons: 1) the subtype avian influenza virus is novel in humans; 2) the cases were from multiple places; 3) the cases’ clinical signs were severe.
Later, more data as I have listed in the paper supported the possible (not 100% certain) great risk of the future development of the outbreak. We did not exclude the possibility that the outbreak will be a just so-so event in the paper. But many people should know the possibility of the reverse, so that they can change their “wait and see” attitude to “properly prepared and see”. Therefore, we wrote and published the paper, with the due historical responsibility of researchers.
I don’t think all scientists agree with our risk analysis, but sometimes people should know different voices, and you can see the similar risk comments published in
Nature on April 2 on the H7N9 outbreak:
Scientists stress that it is much too early to do a full risk assessment of the potential pandemic threat. But the initial analysis of viral sequences is “worrisome” because they show several features that are suggestive of adaptation to humans, says Masato Tashiro, a virologist at the Influenza Virus Research Center in Tokyo, the World Health Organization (WHO) influenza reference and research centre in Japan. The epidemiological picture is troubling too, says Malik Peiris, a flu virologist at the University of Hong Kong. "Any time an animal influenza virus crosses to humans it is a cause for concern, and with three severe cases [of disease] over a short period of time, we certainly have to take it seriously," he says. "There's no obvious indication of human-to-human spread, so we should not overreact, but neither should we be complacent.
Yesterday, an expert from France wrote an email to me stating that he agrees that the H7N9 outbreak represents a distinct pandemic threat.
Possibly you know that humans have overestimated the severity of some possible signs of influenza pandemic in the recent decades, such as the swine influenza outbreak in Fox Dix, New Jersey in 1976, as well as the swine influenza pandemic in 2009. In 1976, a novel swine H1N1 influenza virus circulated exclusively in one site, resulting only one death and 13 hospitalized soldiers. To respond to this possible pandemic sign, the USA government promoted the production of vaccines, and more than 40 million Americans were immunized with the novel vaccines through the promotion. The USA government really responded too much in that case. However, the current H7N9 pandemic signs are much greater than the 1976 pandemic signs. Moreover, we have not thought that we should conduct mass vaccination so far, but we have thought we should build up a stockpile of the H7N9 vaccines as soon as possible in case the pandemic occurs.
I began influenza research nearly fifteen years ago when I was a PhD student in China National Influenza Center, a lab of current China CDC which published this H79 event first. In recent four years, my research group has published a dozen of SCI papers on human or animal influenza virus evolution.
Our risk analysis was mainly based on the wide geographical distribution of human cases, the clinical severity of the cases, and the natural selection driving force acting on the rapid evolving virus when it infects humans and birds. The natural selection driving force in evolutionary biology is very important for us to assess the future development of the H7N9 outbreak, as it can tell us that some dangerous mutants of the H7N9 virus will be favored by the natural selection.
So we published the paper to point the possible (not 100% certain) great risk of the future development of the outbreak, with the due historical responsibility of researchers. Though we are not famous influenza scientists in the world, but we also bear the historical responsibility before a possible (not 100% certain) disaster to let people know the possible (not 100% certain) big disaster risk, so that they can change their “wait and see” attitude to “properly prepared and see” attitude. Actually, we also described the best possible scenario of the future H7N9 development, namely that the virus may disappear naturally, or that the virus is of structural constraints which inhibit any more dangerous mutations.
On other issues of the paper, we accept that the severity rating of infectious disease outbreaks is really crude. But has been there any better methods to rate the severity of infectious disease outbreaks so far in the world? No, there hasn’t. Therefore, we think our crude severity rating method is much better than nothing for this important as well as complicated issue. Otherwise, people do not know the difference among severe outbreaks, very severe outbreaks, too severe outbreaks, in communication and in decision-making. The method which we published in 2010, is really crude, as I have said, but it is simple, practical and worked well when we tested it in rating multiple outbreaks having occurred in recent decades.
I have to say, the severity rating itself is of little importance for the risk analysis, and the rating method has not been accepted by any entities in public health administration. But I have the confidence it will arouse interest of relevant entities in the future.
Regarding the case fatality rate, I also agree that we do not know exactly the real case fatality rate of the disease, as possible some patients infected with the virus have not been identified, and many cases have remained in treatment. Anyway, our estimate of the case fatality rate is scientific based on the observed data at that time, and you can see a similar report published in
New England Journal of Medicine, which stated “To date, the mortality is 21%, but since many of patients with confirmed H7N9 virus infection remain critically ill, we suspect that the mortality may increase.” According to the novel data officially issued on May 1, a total of 127 human cases have been confirmed so far in mainland China, of which 26 died and other 26 have recovered.
Though we have mentioned in the paper that the H7N9 virus may circulate in pigs and horses in the future based on historical information, the paper does not mean that any pigs or horses have been found to be infected with the H7N9 virus. So far, many pigs have been tested in China and no infected pigs have been identified. I think no horses have been ever tested as no epidemiological links have ever been found suggesting that horses, which are very few in the affected regions, played any role in the H7N9 outbreak.
Additionally, from the logo and introduction of your blogs, you underline politics, from the view of an English teacher, and your comments on our paper mainly based on political suspicions, rather than from scientific evidences or inference. Political suspicions and comments on a sensitive issue may cause troubles to innocent authors in most countries who published their risk analysis from their historical responsibility before a possible (not 100% certain) disaster. The paper, like other hundreds of thousand papers from China, was actually published without any go-ahead or permission issued by any authorities. I myself do not know, from your comments, whether you prefer due transparency and due freedom on such an event of international public health concerns, or the reverse.
China has changed greatly since the SARS crisis in 2003, and this time China notified internationally immediately when some labs have confirmed the etiological agent, and reported openly new outbreak and epidemiological data and research news every day. China also shared the virus strain with some international influenza entities. The rising China has taken more and more responsibility in many issues of international significance with close collaboration with international entities.
I wish you good health and happy in this beautiful season with many flowers.
Yours Sincerely,
Ji-Ming Chen
I can add that I do indeed prefer transparency and openness in public health and all scientific issues, and I am delighted with Dr. Chen's response. He has lent credibility not only to his own research, but to that of other researchers in this field, and I look forward to seeing what he and his colleagues report in future.
May 01, 2013 at 05:12 PM
