Regular readers here are aware that the issue of `priming’ peoples' immune systems with a pre-pandemic shot has come up before, as have the considerable obstacles to delivering mass vaccination in the face of an emerging pandemic.
We’ll revisit some of those subjects, but first, take the time to read Helen’s article in its entirety - which includes considerable input from CIDRAP’s Dr. Michael Osterholm.
By: Helen Branswell, Medical Reporter, The Canadian Press
12/05/2010 6:28 PM |
TORONTO - A leading figure in the world of flu is making a bold proposal on how to circumvent too-slow production and too-little output of influenza vaccine during a pandemic.
Dr. Klaus Stohr, former head of the World Health Organization's global influenza program, is suggesting the world consider pre-vaccinating people, giving them protection against strains that could emerge from nature to trigger future pandemics.
In an opinion piece published Thursday in the journal Nature, Stohr argues pre-pandemic immunization may be one of the few solutions to a vexing problem — there is no way to make pandemic vaccine fast enough and in large enough quantities when it is needed to have an impact on the toll the outbreak takes.
Stohr is now vice-president of influenza strategy for Novartis Vaccines and Diagnostics, the world's No. 2 flu vaccine producer and a company which stands to gain significantly if his proposal were to take off.
Still, he insisted that he — not Novartis — is making the proposal because the pandemic response model needs to be fixed and the available options are limited.
"I'm not saying it's simple. I'm not saying it's inexpensive. I'm only saying that there is no other solution I can see," Stohr said in an interview Wednesday.
In just about every book, movie, or TV show about a deadly virus, scientists cobble together some last-minute vaccine, produce it in quantity, and distribute it in the nick of time to save the world.
It is a lovely idea, and a handy resolution for any disaster movie, but it suffers from one fatal flaw: We’ve neither the manufacturing technology,capacity, or the vaccine dispensing infrastructure - to pull off such a feat.
Despite the remarkable global achievement that saw a safe and effective pandemic vaccine begin to roll out less than six months after the isolation of the virus, a combination of supply problems, logistics, an arrival after the peak of the pandemic, and public apathy dramatically reduced its impact.
Five or six months is obviously too long to wait for a vaccine when a novel virus can emerge and circulate widely in a matter of weeks, as did novel H1N1. And even assuming you had the vaccine already in reserve, the problem of dispensing it to billions of people remains.
Some of my blogs on the 2009 pandemic vaccination experience include:
The solution proposed by Klaus Stohr is to prime people’s immune systems with a pre-pandemic vaccination.
The hope being that even if it wasn’t a perfect match to the next emerging influenza virus, having similar antibodies may convey some protection, and that a single `booster’ shot might be all that was required.
And if fact, this tried in Japan back in 2008, when their limited stockpile of H5N1 bird flu vaccine was about to expire. They decided to `store it’ in the arms of healthcare and public safety workers, rather than pour it down the drain.
Of course, we won’t know if this little experiment works unless an H5N1 pandemic breaks out, and recipients of this vaccine are shown to have fared better than those who weren’t `primed’.
The idea is rooted in science, however, for in the summer of 2008 we saw a study, published in the August edition of The Journal of Infectious Diseases, which showed that people who received an experimental H5N1 vaccine in Hong Kong 8 years before developed a strong immune response after receiving a single booster shot of a clade 1 H5N1 vaccine.
Other countries, including the UK, have considered similar strategies (see UK: Considering A `Prime Directive'). But in these instances, countries already have an H5 vaccine on hand, and it is generally a `use them or lose them’ decision.
The big problem is, as Dr. Osterholm points out, no one knows what the next emerging virus is going to be (H2? H5? H7? H9?). And the experience with novel H1N1 has shown that having had an H1 vaccination (or exposure) in the past was no guarantee of immunity.
Simply put, a pre-pandemic vaccine might miss the antigenic mark by a considerable margin and provide little or no protection.
Add to that the costs, safety concerns, public ambivalence, and the sheer logistics of delivering a pre-pandemic shot to (potentially) billions of people, and you have a pretty hard sell.
While I might be willing to accept a seasonal flu jab with a bit of H5 or H7 antigen thrown in for good measure, there would likely be considerable public resistance to the idea.
Conspiracy theorists would have a field day, and any reports of side effects (real or imagined) would likely quickly cool public ardor for the shot.
As both Osterholm and Stohr point out, the system in place now is inadequate to deal with a severe pandemic, and better solutions are desperately needed.
One such solution would be the development of a universal flu vaccine, the `holy grail’ of influenza vaccinology. One that targets a conserved epitope common across a wide range of flu viruses, and would convey protection against many strains.
It wouldn’t solve all of the problems, but it would be a huge step forward.
That solution, at best, is still likely a number of years away.
Meanwhile, the debate over how to deal with the next emerging public health threat continues, and good answers remain in distressingly short supply.