Comments on: Poliovirus vaccine safety

By: PhilMcD

PhilMcD — Wed, 14 Apr 2010 11:41:28 +0000

Why not vaccinate with inactivated polio virus first and follow up with OPV. The inactivated virus should be able to stimulate a systemic immune response which would prevent significant systemic replication of OPV that is given at a later time, and therefore lessen the chance of reversion to virulence. The purpose of the OPV used subsequently would be to stimulate IgA mediated mucosal immunity, if the inactivated vaccine had failed to do so initially. Not sure how practical it would be, but theoretically it sounds like it might work.

By: PhilMcD

PhilMcD — Wed, 14 Apr 2010 04:41:28 +0000

By: pteropid

pteropid — Mon, 12 Apr 2010 18:47:00 +0000

Hi Guys,

We know that attenuated poliovirus can be implicated in VAPP cases, but what about transverse myelitis, which is considered to be a host mediated immune response gone wrong. From my understanding wild poliovirus can cause transverse myelitis, but it seems that the scientific community is sceptical about the vaccines ability to induce transverse myelitis. My colleagues and I investigated such a case, http://www.journalofclinicalvirology.com/articl... , and would be genuinely interested in your opinions, as I have been engagd in heated arguments about the vaccines role in this condition with other colleagues.

By: Jparilla

Jparilla — Mon, 12 Apr 2010 14:35:27 +0000

Unfortunately, the IPV (inactivated poliovirus vaccine) does not give as strong of an immune response as the OPV (oral poliovirus vaccine) – especially for secreted IgA antibodies which may be very important for polio immunity. This isn't as much of a concern for polio-free countries, but in areas of the world where polio is still endemic – the added immunity received from OPV may be very important. Also, OPV can be administered without trained medical personnel, which makes the massive polio vaccine administration fiscally feasible in countries like India.

By: dmcilroy

dmcilroy — Sat, 10 Apr 2010 18:42:06 +0000

Injectable polio vaccine has inactivated virus, so there is no possibility of the vaccine reverting to a more virulent strain in the body. In the US, only injectable polio vaccine has been used since 2000. So I would say that this problem has been adequately adressed by changes in the type of vaccine used - in the US, and many countries in europe at least.

http://www.cdc.gov/vaccines/vpd-vac/polio/defau...

By: sciguy

sciguy — Sat, 10 Apr 2010 10:19:21 +0000

This is precisely the reason that Dr. Racaniello's (and his colleagues) basic research is so important. Understanding the nature of these mutations, how they work in concert with each other, and how they revert is no small feat. Keep in mind how incredibly safe vaccines are compared to the alternative: how many people do you know in iron lungs today? We'll always strive to make it safer but there will always be some measure of risk. Going from tens of thousands of cases/year to 5-10/year from the vaccine seems like a pretty good trade off to me. Everyone would love zero but it might not be biologically possible, and no one should demand zero risk. Cars continue to kill quite a few more people than vaccines but most of us continue to accept this risk. And, unlike cars, there is no consequence of not using cars (well, except that it will become pretty hard to get anywhere).

By: gitster

gitster — Fri, 09 Apr 2010 19:37:16 +0000

To a lay-person, it does not make much of material difference if the original vaccine preparation already had virulent virus particles, or it merely contained virus particles that could mutate to become virulent. Are there efforts to make the mutation that make the vaccine avirulent more stable?

By: CBS

CBS — Fri, 09 Apr 2010 19:24:54 +0000

Would it beenefit or harm if the population was explicitly made aware of this information prior to vaccination? In the scenario you describe for polio vaccine, I'm pretty sure that 5 to 10 people a year would lean very strongly towards truly informed consent before vaccination. As for the balance of the population, I'd like to know but how many people would decline vaccination and get (and then spread) polio?

Earlier posts have talked about the credibility of science within the general population. Any thoughts on truly informed consent and easy to understand explanations for patients before being vaccinated?