Replies

Herd immunitity is the reason we need new smallpox vaccinces that are at least a couple of orders of magnitide safer. If we had much safer smallpox vaccines, vaccination could once again become routine. A high level of herd immunitity would be a tremendous deterrent to a biowarfare attack. The fact that less developed countries might opt not to vaccinate against extinct diseases such as smallpox would be a deterrent for terrorist from those countries attempting an attack on the US. They would be more likey to cause an outbreak in their own countries than in the US.

The type of vaccines needed to maintain herd immunity are likey to be different than the types used to stop an outbreak. For example the live oral polio vaccine causes a the immune system to build immunity faster than the killed version. Unfortunately the live polio vaccine sometimes mutates back to the virulent form and causes polio. While the live vaccine is no longer used in this country due to the rare but devastating side effect, it is used in countries like Afghanistan where polio is still endemic. If the US were to develop safer inactivated smallpox vaccines, the live vaccine would still be useful in case of an outbreak, because it can be given up to four days after exposure to smallpox.

We need to have bettter forethought about how diseases are exterminated in the future. If we stop vaccinating against polio after polio is erradicated, in thirty years or so we would have same kind of vulnerabilty to polio attacks as we now have to smallpox. After polio is "erradicated," WHO wants to erradicate the measles. We certainly don't want to repeat the same mistakes with the measles that have been made with smallpox. All it takes is for someone to clandestinely freeze some samples of the virus.

I agree with your observations. Orimune was a fantastic vaccine for rapid and cheap vaccination campaigns. However, the incidence of vaccine associated paralytic polio were unacceptably high (5-10 cases per year in the US).

Prior to banning OPV, the ACIP should have undertaken analysis of the combined regimen which they had recommended for several years. Until 1999-2000, ACIP had equal recommendations behind full OPV, full IPV, and partial IPV/OPV regimens.

I still feel that initial immunization with IPV twice, followed by OPV later in life would prevent the cases of VAPP. This is relevant because OPV is much cheaper and easier to use than IPV (OPV is an oral drop, but IPV is injectable).

Regarding the future eradication of Measles or Polio, the regimen for immunization would likely change once the disease is exterminated. Instead of giving so many injections, you would likely given one vaccine at 4-6 years of age for MMR and IPV. You would probably be able to eliminate 3 doses of polio vaccine and 1 dose of MMR. That will save our nation $160.00 per child.