Wednesday 8 May 2013

Losing control of the numbers?

That's how it was described to me by my esteemed colleague, the Editor in Chief of FluTrackers. 

For the past 5 week we've had fairly detailed data coming out of China about avian influenza A(H7N9) cases; dates, places, names, deaths, discharges., All these placed into the public domain and not just reported to Health officials through less public channels. 

Sure, I've griped about a missing number here and there in the past, but its not like I have a right to this information. Are these the data I'd like to see? No, I'd like to have seen prospective real-time RT-PCR-based (couple of assays targeting different regions) screening hospital outpatients, the community and including asymptomatic people, of all ages. I'd like to see serology on the vendors and those who frequently visit markets versus those who do not. And I'd like it all done yesterday. But that's flippant, and easy to say from my desk in my environment of instant gratification, some 7,330km away. Are these data from every single H7N9 case? Probably not, for a number of reasons. So, for some pure speculation. 

It just doesn't feel right. 130 cases spread over such a wide area, steep onset curves that suddenly halt, patents like Lee from Taiwan and others who claim no bird contact, so few severe cases among market vendors, evidence for asymptomatic and suspected clusters. 130 cases seems too low. More unreported cases may exist simply because we don't have all the results yet. Those may be coming down the pipeline. The time and effort to conduct screening and sequencing, collate data, cross-check and report results for humans and animals on the scale that is necessary to answer the questions being posed, is vast. China needs to juggle many other social and political issues around the reporting of deaths, illnesses and human-to-human transmission of this new virus. It has its own way of doing that. Most states do.

Nonetheless, scientists, policy makers, healthcare officials and vaccine producers (traditional and cutting edge) already have the information they need to get started on preparing for any future H7N9 pandemic.

  • Vaccine seed strains have been circulated worldwide
  • WHO influenza collaboration centres have positive H7N9 RNA controls for their RT-PCRs
  • More RT-PCRs have since been developed to overcome the (not unexpected) deficiencies in first-generation assays
  • Serological reagents are in use in China and in preparation elsewhere
  • Key global health bodies have updated their pandemic plans
  • We have estimates of incubation periods, clinical signs and symptoms indicating that severe acute respiratory disease cases look like....severe acute respiratory disease cases would be expected to look
  • We know transmission may be happening between humans but inefficiently
  • We know closing down wholesale poultry markets seems to correlate with a decrease in severe H7N9 cases in humans
  • We've dusted off (ineffective) heat sensing cameras and (pointlessly) ill-fitting face masks again
  • We have a good idea of what the wild host is (a it is for all influenza A viruses) just not evidence for which one or where it all started
  • We've officially named our viral nemesis.

So all in all, we're not too badly off.

However Week 6, so far, has provided confirmation that publicly available case details have almost dried up.
The data we've had have been interesting and have allowed me to plot the detailed charts and graphs you've been viewing on the H7N9 page. Half of those views are from repeat visits. 

Today, my last hope faded for an update on those details for the recent 6 H7N9 deaths and the missing details on about 15 discharged patients. The WHO update had no new information in it at all. Perhaps other lists will be updated soon?

Here's hoping for some new data in the future, especially if that data should signal to the rest of the world that H7N9 has changed genetically, or a return of exponential rises in new H7N9 illness onsets such as we saw in Shanghai and Zhejiang. 

I think we have what we need to know that an H7N9 pandemic could emerge, but that one hasn't emerged yet.

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