Is HIV just an unusually strange or difficult virus to develop a vaccine for? Or is it possible there will be NO vaccine for Covid-19?
I suspect is has something to do with HIV causing AIDS which is an autoimmune disease. Vaccines rely on teaching your immune system how to target the virus, but HIV targets the immune system. Now that I’m thinking about it though I realize I don’t know this, it just seems right-- I will do some research.
HIV is definitely an unusual case. Retroviruses are very different.
It is quite possible we will never have a vaccine. There is no vaccine for any coronavirus, and so no guarantee one can be successfully created for this one. It’s really LIKELY one can be created… it is apparent a person can be infected with SARS-CoV-2, beat it, and then be immune, which isn’t the case for HIV. A vaccine does the same thing, just without the “Getting really sick” part. There’s no guarantees though.
Yes it is possible that the efforts will fail. However the efforts being expended on a COVID19 vaccine far outstrip what was and has been done for HIV*, since the former is much more “bad”, disease, since although AIDS was lousy for the people it hit and their loved ones and communities (panache45 has written about it at some length), it did not cause a anything resembling the current global shutdown (and this is a disease which at times looked like it might be the modern Black Death or Plague of Justinian in sub Saharan Africa).
*A lot of the pressure for a vaccine for HIV has receded as newer drugs permit a longer lifespan (approximating a natural one) and can keep the disease managed, it’s almost a chronic condition like diabetes these days.
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Maybe because HIV does not go away on its own but Corona virus goes away on its own in the people who don’t die of it
Cutting and pasting from Wikipedia since it seems like a fairly succinct write up:
However, the classical vaccination approach that is successful in the control of other viral diseases - priming the adaptive immunity to recognize the viral envelope proteins - did not work against HIV. Many factors make the development of an HIV vaccine different from other classic vaccines:[7]
- Classic vaccines mimic natural immunity against reinfection as seen in individuals recovered from infection; there are almost no recovered AIDS patients.[citation needed]
- Most vaccines protect against disease, not against infection; HIV infection may remain latent for long periods before causing AIDS.
- Most effective vaccines are whole-killed or live-attenuated organisms; killed HIV-1 does not retain antigenicity and the use of a live retrovirus vaccine raises safety issues.
Currently, there is no licensed HIV vaccine on the market, but multiple research projects are trying to find an effective vaccine. There is evidence from humans that a vaccine may be possible. Some, but certainly not all, HIV-infected individuals naturally produce broadly neutralizing antibodies which keep the virus suppressed and these people remain asymptomatic for decades. Potential broadly neutralizing antibodies have been cloned in the laboratory (monoclonal antibodies) and are being tested in passive vaccination clinical trials.
Many trials have shown no efficacy but one HIV vaccine regimen, RV 144, has been shown to prevent HIV in some individuals in Thailand.
According to this article, the autoimmune bit is one of three factors making an HIV vaccine difficult.
First, HIV replicates very quickly and makes lots of errors when doing so, leading to 60 known strains of the virus, each of which may require its own vaccine.
Second, HIV is good at hiding from the immune system once it’s in the blood. Even if the body knows what to do when it finds an HIV particle, it can’t stop the infection if it can’t find the HIV.
Third, it’s the fact that as an autoimmune targeting virus HIV actually kills the cells that are supposed to kill it.
It’s because HIV is a retrovirus. It uses an enzyme to convert its RNA to DNA once it finds a host. Coronaviruses are not retroviruses.
To kinda package a lot of what we’ve already said into one post – the body can beat a normal virus when in good condition. When someone gets a virus, we can make their body into a more hostile environment for the virus or keep them alive when their symptoms would have killed them, but what really ends the infection is their own immune system. A vaccine is a way to teach the body the lessons it would learn in the course of fighting a disease, without actually having the disease. But since the body cannot effectively fight HIV (because it replicates quickly and mutates, because it targets the immune system, and because it can hide very effectively) there isn’t a lesson we can teach the body to handle the infection on its own – yet, at least.
Does that sound right?
A better comparison would actually be how quickly a vaccine was developed for Ebola once it was up against first world resources.
Also, when a really concerted effort began to seek a vaccine for polio, a vaccine was developed in a matter of years. After the Rubella epidemic of 1965-67, a vaccine was developed in about two years, all without 21st century technology.
We already know ~100x more about Covid-19 than we did a month ago.
IANAD, but I have a cousin who is a PhD-type doctor, a virologist, and was on the Ebola vaccine team. She drops tidbits for me. I also know a lot about vaccine history because I read a lot back when I thought it was possible to argue with anti-vaxxers.
When I was in high school, our biology teacher gave the following description of how the immune system works:
Within our blood are some little guys (antigen-presenting cells?) who, when they identify a disease, they tear its limbs and face off and dangle them from a bar that they hold over head. They then run around, showing the body parts to T-cells, to know what to look for. If a T-cells recognizes any diseases that it has been told to look for, it’ll beat it up and tear it apart.
The goal of a vaccine is to present an already dead virus to the body in such a way that the APCs pick them up and start carrying them around.
I believe that “antigenicity” means that when you tear apart an HIV, the body parts are always too mangled to be usable as a defense. They’re not recognizable as the live virus.
And they’re confident that we will have a vaccine for this virus because we already do. Several of them, in fact. The long time frame isn’t to develop the vaccine; it’s to prove that it’s safe.
Vaccines need to clear a fairly high bar for safety, because they’re given to healthy people: If you have a medicine that has a 50-50 shot of working or killing you in a year, and you only give it to people who are so sick that they won’t live a year without it, well, you use that medicine (at least, if you don’t have anything better), because it won’t make things any worse. But when you’re giving something to healthy people, there’s plenty of room to make things worse, and so you need to be more careful.
Is there any benefit to giving vaccines to newly sick people, even a minor benefit? Would injecting lots of the inactive virus help the body react quicker and stronger against the real virus, or would it be irrelevant at the point at which someone is already sick with the real virus?
Well, there are no vaccines against any retrovirus, as far as I understand it. “Retrovirus” is a category of virus that is DIFFERENT from the category Covid-19 belongs to. Covid-19 is a coronavirus. Retroviruses rely on an enzyme called “reverse transcriptase” to convert their RNA into DNA. This makes them a new kind of organism, so they would evade vaccine created immunity based on the RNA form, and attacking the DNA form is problematic for reasons I do not fully understand.
Don’t quote me on this next part, because I may be misunderstanding, or grossly oversimplifying, but I think the medication PrEP (Truvera), that HIV- people at greater risk for being exposed to HIV take daily to reduce their risk, works by neutralizing reverse transcriptase. So it stops the RNA-DNA conversion process, and your immune system can eliminate the virus. I don’t think that people on PrEP who are exposed to and eliminate HIV as RNA gain immunity, though, but again, don’t quote me.
IIRC (again, don’t quote me), because HIV mutates quickly, there has been a problem getting animal models for HIV to do research.
I have Googled all this, and not got very satisfactory answers. I would email my cousin, but she is trying to cope with a 1-year-old, and a job that has NOT furloughed her, and a daycare that has. I have never been so glad my son is a teenager who likes to shut himself in his room and park himself in front of the computer.
That “-” is a tilda when I’m typing. It looks like a tilda now. That should be read “more or less 100x what we know about Covid-19…” Not “minus 100x what we know…”
ETA: Oh, sure, now in the quote, it looks like a tilda.
Interesting question.
When you’re exposed to rabies, they give you a series of rabies shots - which involve immunolobulin and vaccine (I had to check, as I wasn’t sure about the vaccine part).
After some injuries, you might also be given a tetanus booster vaccination. .
I don’t know if there are similar protocols for any other vaccine-preventable illnesses.
Whether such a thing would be helpful in COVID, obviously I have no clue - but it’s not an outlandish question.
Of all the differences, this is the first “They are not at all alike.” one.
You get HIV, you are going to have it forever. Well … until you die if you aren’t treated. Your body doesn’t fight it well.
You get CV, your body fights it. Often well enough so you survive.
So there is clearly an effective immune response to CV. That is a very positive indication that a vaccine is possible compared to HIV.
Ebola virus was identified in 1976. Ebola vaccine development began shortly thereafter back in the 1970s. Animal studies were published in The Lancet by December 1980.
Certainly resources were ramped up greatly after the West African outbreak, but they were not starting from scratch.
However we are not starting totally from scratch with the current coronavirus outbreak. Current work will build upon efforts that began with the SARS and MERS outbreaks. Moreover technology has developed significantly allowing much faster development.
OK; but the bit about HIV being a retrovirus is much more relevant. There may never be an HIV vaccine, so it is dealt with in other ways. From what I understand, though, there is no reason to believe a vaccine against a coronavirus can’t be developed.
The trick with immunisation is that it gives the body a head start. There is a race between the infecting virus/pathogen and the immune system. In your body the virus is replicating, and doing so roughly exponentially. Your body will normally recognise the non-self pathogen and start the immune system’s pipeline to generate a targeted response. But this takes time. During this time the virus is spreading faster and faster. Normally the body will eventually get enough of an immune response going that it will mop up the infection and you will recover. If it can’t mop up fast enough, you are in a world of trouble. But if the immune system already has jumped the first few steps of the response pipeline it is ahead of the game, and given the exponential reproduction rates involved, this can mean a very big gain. So much of a gain that you may never actually notice that you have been infected.
Rabies is interesting. Once bitten the virus replicates very slowly. Sufficiently slowly that you have a window of opportunity to teach the immune system about it. But, for all useful purposes, once you are symptomatic it is too late, and you are going to die. Again, the nature of exponential increase.