the more people vaccinated the lower the odds of new mutations right? but since the virus can live in animals is there also a meaningful risk that the virus will evolve in other mammals and end up immune to vaccines?
how hard would it be to make a new vaccine against a new strain? will it take an additional year of testing or can they just tweak the mRNA sequence and release an updated vaccine in a week?
I’ve heard it could take several years to vaccinate the entire world, I’m worried that even if we get a billion people vaccinated that’s still an additional 7 billion for the virus to evolve in. not to mention all the other animals that can get it.
Seems likely that it can mutate in other animals and reenter the human population. There was an article in the NY Times about that very concern and how the virus might be a permanent, continuously evolving problem.
Um… yes. But it can also mutate so that it can only live in animals and not infected humans anymore. Or the virus in humans could mutate so it could live only in human. Or become less infectious or more infectious or more serious or less serious…
Mutation is random. It can go in any direction.
Probably less difficult than making the original vaccine.
My understanding is that for the mRNA vaccines (Pfizer, Moderna) they can just tweak the mRNA sequence. The Johnson & Johnson ones is more traditional and most require developing a new version of the vaccine. Not sure how much additional testing would be required.
Yes, generally it does take a “couple years” to vaccinate everyone. It took decades to eradicate smallpox via vaccination once we got serious about trying to eliminate it. Polio is almost gone, that’s also taken decades, since the 1940’s.
So if we can get everyone vaccinated against covid in just a couple years we’re actually doing really, really good.
And you point about having 7 billion other hosts to breed in is exactly why the wealthy nations need to fork out to get the poor nations vaccinated instead of waiting until the poor can afford it.
It only took them a weekend to tweak the mRNA sequence back over a year ago; it’s all the testing that takes time. I imagine that it would work much like a flu shot, in that I doubt that every year’s tweak for the expected strains has to re-undergo the safety and efficacy testing each time.
mutation is random yes, but one that is able to outmaneuver the vaccination produced antibodies would spread wildly. I don’t even know how many variants there are now, but I thought at least one variant that has already evolved was already immune to vaccines, which not only means vaccinated people could get it but people who’ve already had SARS-Cov2 can catch it a second time.
Also if we tweak the mRNA, isn’t there a risk that the new protein structure could cause issues like autoimmune attacks or other issues unless we do another year of three phases of FDA trials? I don’t know if every mRNA vaccine variant we make will require lots of testing to determine if its safe.
The flu vaccine was mentioned, but isn’t the flu vaccine just different combinations of vaccines for various H and N proteins that are already known and that we already have vaccines for, which is different than a novel coronavirus with an entirely new protein structure I’d assume regarding vaccine safety.
If you’re talking about the South Africa variant, some vaccines seem to work better against it than others, and there seemed to be some evidence that people who’d recovered from an earlier version of SARS-coV-2 could be reinfected by the variant. But that doesn’t necessarily mean that the less effective vaccines were completely ineffective, or that previous infection has no protective effect.
I’m not sure if anyone has actually studied those questions, or made conclusions about them available. I think what we have might just be things that are suggested by data in studies that are investigating something else (like effectiveness against symptomatic Covid at all).
Like, a vaccine might show a similar number of total infections with a variant as a placebo, but there could be differences in severity of illness, so the vaccine might still be beneficial.
No more so that the older variants could “spread wildly” prior to the availability of vaccines.
There is the problem of vaccine overconfidence, the rolling back of restrictions because YAY, VACCINE before we are actually getting a real grip on all this.
Not completely immune, but variants against which both vaccine-generated immunity and natural immunity are less effective. That means that instead of preventing illness entirely you’d get sick, but not badly enough to need to go into a hospital, as an example of how that could work.
There have been a few people who had the original variant who also caught it twice, but they’re rare. It is unlikely that either prior infection or vaccination would leave you entirely without protection against a new variant. Possible, but not likely.
Autoimmune/allergic reactions with the mRNA vaccines are rare. Yes, they occur, but not even every highly allergic person (such as myself) will have a bad reaction (mine, in fact, was an average to milder than average reaction to my first shot). Those are a risk with any vaccine.
How much testing would be required probably depends on how much tweaking is required and is beyond my ability to speculate intelligently. Minor changes would probably require no more testing than each year’s new iteration of flu shots. I don’t know the point at which it would be considered sufficiently different to require a complete new set of clinical trials.
I think that’s a fair assessment of flu vaccines, but it’s not like those are without risk. I mean, I’m allergic to flu vaccines myself so there are a known subset of people who have issues with it. From my limited knowledge (which may not be 100% accurate so keep that in mind) the mRNA covid vaccines are actually pretty safe compared to other vaccines, they aren’t having greater problems than other common vaccines. Problems are more noticed with covid vaccines because covid is in the news.
I gave an update on this in another thread. I’ll just copy the post over to here. TLDR: No (big, slow) clinical efficacy studies. Is the immune system response for new variant/new vaccine the same as for Original SARS/original vaccine? Yes? Then we’re good to go.
(Earlier post follows:)
So: about these COVID variants - we’re going to have to tweak existing vaccines in order to provide protection against them, right? But how do we test the revised vaccines for efficacy before they are made available?
The European Medicines Agency released a reflection paper [Link is to PDF] today - a reflection paper being pretty much what it says - the agency is sharing its thoughts with us; in due course, and taking account of comments from medical, industry and other experts, this will become a guideline which tells you what you have to do.
The (current) EMA position is that no large scale efficacy studies will be required; approval of the updated vaccine - presuming that it is formulated, manufactured, tested etc etc like the “parent” vaccine was - will be based on human immunogenicity studies. Basically, trial subjects get a shot of the vaccine, their immune response gets tested to show that the new vaccine does the same thing against the new strain, compared to old vaccine/old strain. The paper covers combi vaccines (old + new in a single shot) - the approach is similar but (obviously) a bit more complicated. Safety data for authorisation would come from the subjects included in these studies.
The FDA moved faster (I was a couple of days late getting to this) and have already revised existing guidance. As you would hope, they are thinking pretty much along the same lines as the EMA. Link to announcement (from which you can hunt down the guidance document, if you wish).
The updated guidance outlines the FDA’s scientific recommendations for modifications to authorized vaccines. For example, the FDA expects that manufacturing information will remain generally the same for an authorized vaccine and a modified vaccine candidate from the same manufacturer. For clinical data, the guidance recommends that a determination of effectiveness be supported by data from clinical immunogenicity studies, which would compare a recipient’s immune response to virus variants induced by the modified vaccine against the immune response to the authorized vaccine. Manufacturers are also encouraged to study the modified vaccine in both naïve (non-vaccinated) individuals and in individuals previously vaccinated with the authorized vaccine. Additionally, the guidance outlines the FDA’s recommendations for assessments of safety to support an EUA for a modified vaccine. Finally, the guidance states that further discussions will be necessary to decide whether in the future, modified COVID-19 vaccines may be authorized without the need for clinical studies.
Obviously this is just a very brief summary of the documents. If you have questions, I can try to field them, but I’m not an immunologist…
I know your question is about how likely a new variant evolves, but this is encouraging about the current state of the world and immune responses to the current variants:
In laboratory tests, T-cell responses in those vaccinated or previously infected with coronavirus were largely unaffected by each of the key variants. This included the new Brazilian varian, found in small numbers in the UK last week.
…
One of the concerns about new variants, particularly those from South Africa and Brazil, is they contain a mutation that changes the shape of the spike, meaning they evade antibodies built up against the old version.
However, that is only the first line of defence. We know from vaccine trials that even if people do become infected following vaccination, they are still at least 50 per cent less likely to develop severe disease compared with those who were infected without being vaccinated.
The second line of defence that helps them to fight off Covid comes in part from T-cells, which are harder to trick.
“One of the things that T-cells do is kill infected cells or create an antiviral response,” Sette said. “So, if you have T-cells you may not prevent the infection, but you may lessen the severity of the disease. You may also shorten the duration of a disease.”