question about live virus vaccines

[tatsu15]

I've been reading articles stating that live virus vaccines offer lifelong immunity and better protection than the dead virus vaccines.

But I also read that live virus vaccines can be more harmful. My question is why do live virus vaccines pose more of a threat as opposed to dead virus vaccines? Thanks in advance!

[Deborah]

Definitely not lifelong immunity.

See boosters recommended for measles, mumps and rubella (MMR) vaccines, for an example.

[just_lily]

It poses more of a threat because it has the potential to cause the disease you are supposedly vaccinating against in the first place. It also can shed, and cause the disease in people around you. This is especially true for oral vaccines that can shed in stool, like rota and oral polio.

And they definitely don't provide life long immunity. MMR now has two doses, and 'they' are contemplating a third. Nobody seems to know how long CP will last.

[Andreas]

There are other risks involved in a live vaccination, in particular the combined vaccines like MMR.

By the simultaneous administration of multiple vaccines, especially live vaccines there is the risk that an induced immune system (through the vaccine) causes a persistence of a virus in the body without eliciting an immune response to the virus. This virus can then possibly lead later to a chronic disease.

For example it is impossible that you have two viral disease at once(e.g.measles and mumps, I am not talking about Hepatitis B and C). You might have measles and afterwards you get mumps, but not at the same time.

Maybe this is of some help

Andi