Vaccines usually work using a version of the pathogen that's been weakened or killed such that it won't infect the patient but is still recognizable to their immune system. These are usually viruses but sometimes also bacteria. My idea works only for the viruses, unless someone comes up with a way to have a virus induce its host cell to make a believable fake bacterium.
First, weaken/kill the pathogenic virus in question by modifying its genome in a repeatable way, rather than by exposing it to some external weakening factor (such as ionizing radiation or toxic chemicals) that causes injuries to its already-constructed body. The reason will become more obvious later. It shouldn't be too hard to find some ways to change its genome that cause it to stop working as a virus but that don't change how it appears to the immune system. Maybe just edit out or corrupt the code for the mechanism it uses to enter host cells, or that for the mechanism it uses to hijack the host cell's replication apparatus?
Anyway, once that modified genome of the pathogenic virus is created, get some other virus. (I suggest starting with a rhinovirus, such as usually causes the common cold.*) I'll call this one the carrier. Modify this virus's genome too, to make it more virulent but less illness-causing (ideally not illness-causing at all, except maybe for causing sneezing so it can spread).
Then modify the carrier's genome further, by inserting the previously modified genome of the pathogen and programming the carrier to replicate that in addition to itself once it's infected a host cell. That's why the pathogen must be weakened at the genetic level: that's the only kind of weakening that will survive being carried to the host in genetic form only.
Then release the carrier into the wild by infecting a bunch of members of the public with it. Hopefully, the majority of the public will be infected by the carrier, and then get immunity to not only the carrier but also the pathogen that is its payload.
*Why: 1. They don't usually make people that sick, so it should be safer even if the modification to reduce illness-causing-ness fails. 2. Nobody has been able to develop a vaccine against them yet, and there's a great variety of them, so it should be possible to use a new version (possibly even with engineered identifying features, for more uniqueness) for each viral vaccination campaign so that people's immune systems don't fight off the carriers before they've delivered their payload.
N/A [2020-03-15]-- notexactly, Mar 15 2020 the virus itself accomplishes this, albeit at a very high cost-- theircompetitor, Mar 15 2020 // a very high cost //
"Very high" does not mean "excessively high" or "unacceptable", however.
As in all such things, the costs and benefits must be apportioned and compared.
For example, constructing major bridges and tunnels have "a very high cost", yet these projects are executed, since the perceived return (or eventual saving) is calculated to meet or exceed the outlay.
Consider the following, based on Utilitarian Ethics:
The lives of 100 healthy humans can be extended by, on average, 20 years, by cutting up one healthy human into 100 portions and giving one prepared portion to each recipient.
The obvious course of action is to select an individual of limited value to society (in terms of productivity) and get busy with a cleaver.
Yet this would be unacceptable to the great majority of the population (and particularly to the one who gets chopped up).
However, given the option of "Push this button and someone you don't know will die, but you will live an extra 20 healthy years - and no-one else will ever know", how many people would do it ?
Given that humans are nothing more than greedy, venal, selfish little lumps of ego, scrabbling to get further up the vast, festering antheap of society, and treading on the faces of those below as they go, our estimation is "lots" ...-- 8th of 7, Mar 15 2020 // the virus itself accomplishes this, albeit at a very high cost //
The cost of my plan is also probably pretty high. It's just a question of whether we want to have a high healthcare cost or a high R&D cost. The latter seems preferable not only because it results in less suffering but also because it gains us knowledge and skills that we can apply to other things.
// The lives of 100 healthy humans can be extended by, on average, 20 years, by cutting up one healthy human into 100 portions and giving one prepared portion to each recipient. //
Explain?-- notexactly, Mar 15 2020 Yes, it's a thought experiment.
At the moment, anyway.-- 8th of 7, Mar 15 2020 How exactly does the one virus piggyback on the other? I'm a little lost there.-- RayfordSteele, Mar 16 2020 I think what's envisaged is more like a pig-centaur than a pig-and-jockey.
I'd be very surprised if it worked, but I think that's how it's *meant* to work.
What would make me surprised is that we'd be trying to make a virus whose surface resembled that of a dangerous pathogen - enough to make antibodies which learn to attack it also attack the pathogen - but whose interaction with the human body would induce sneezing but no other significant symptoms.
Now, I'm not a biologist, but my hunch is that the interface of a virus as experienced by an antibody is somehow related to the interface of the same virus as experienced by ... whatever triggers the sneezing reflex. The virus only has one physical / chemical surface.
If we were doing software engineering, we could specify a class which implemented both IMakeYouSneeze and ITrainYourImmuneSystem, and the calling code could call methods from one or the other as desired. But we're not doing software engineering, and the host body will not make purposive calls to parts of the virus' surface; rather, the virus and parts of the host body will just bump into each other, with no means of separating the two interfaces or picking one.-- pertinax, Mar 16 2020 //At the moment, anyway//
How did he escape? Have you still not fixed that sash window on level three?-- pertinax, Mar 16 2020 No, and we've oiled the runners so it slides silently.
The mechanism is the same as the smallpox/cowpox immunization, where the relatvely harmless organism expresses many of the same proteins as the dangerous one, thus immunity to one is immunity to the other.-- 8th of 7, Mar 16 2020 ... my point being that cowpox was, in its symptoms (and, presumably, in its bio-chemical modus operandi), a milder version of smallpox, in much the same way that the common cold is *not* a milder version of, say, AIDS.-- pertinax, Mar 16 2020 // What would make me surprised is that we'd be trying to make a virus whose surface resembled that of a dangerous pathogen - enough to make antibodies which learn to attack it also attack the pathogen - but whose interaction with the human body would induce sneezing but no other significant symptoms. //
It's not one virus that does both. The carrier induces sneezing so that it can spread. The payload is what looks like the immunization target to antibodies. After this virus-with-a-virus-inside has gone through you, you're immune to both the carrier and the payload/target. The payload doesn't exist in physical form outside of a host, while the carrier does, so that it can be transmitted.-- notexactly, Mar 20 2020 random, halfbakery