> Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.
There cannot be a the vaccine; obviously, SARS-CoV-2 vaccines will have to be updated. People will need boosters.
> I've still not heard a reasonable explanation about why this vaccine is expected to work long-term when the flu shot clearly does not
I don't think anyone in their right mind claims or believes such a thing, or believes that the health authorities are trying to convince them of such a thing. Depending on what we mean by "long term".
I'm skeptical about the efficacy of the SARS-CoV-2 vaccine over longer periods of time.
I've still not heard a reasonable explanation about why this vaccine is expected to work long-term when the flu shot clearly does not. Especially since SARS-CoV-2 mutates faster than the flu virus.
Can anyone give me an explanation of why vaccines are touted for fast-evolving viruses like the flu and SARS-CoV-2?
it almost certainly is mutated at least some to further evade the vaccine. by the time the vaccine came out, COVID had already mutated enough to reduce the effectiveness of the vaccine. Which is why the original predictions that it would keep you from getting or spreading COVID turned out to be overstated. That's not to say it doesn't reduce the chances, but it seems likely as the virus continues to mutate, the effectiveness will reduce until it gets updated.
All viruses mutate, but so far SARS-CoV-2 has been mutating relatively slowly. It has an error correction mechanism which blocks the majority of mutations. By contrast influenza lacks that error correction and mutates much faster, which is why we need a reformulated vaccine every year.
The human species already has a significant level of herd immunity against four other endemic coronaviruses. The same thing will eventually happen with SARS-CoV-2 one way or another, but hopefully we will have an effective vaccine soon enough to accelerate that process while minimizing the death toll.
Not exactly sure, but I think the original version of the covid vaccine has been good enough for the mutations and there has not been need for modified version.
Corona viruses are slow to mutate in general, and flu is especially fast.
That's why you need a new flu vaccine every year - every year a lot of time is (was?) invested in tracking what flu mutations are appearing and trying to predict which ones will be the main ones next year. Once they've determined what they think are most likely, the vaccines are developed for those. Happily flu mutations mostly impact the protein structures sticking out of the virus wall (the HxNy is an actual description of these proteins, hemagglutinin and neuraminidase), so it's mostly a matter of retargeting an existing set of vaccines rather than creating a whole new vaccine from scratch.
The UK government has stated that there is no evidence the vaccine will not be effective against this strain. And from the bmj:
The new variant has mutations to the spike protein that the three leading vaccines are targeting. However, vaccines produce antibodies against many regions in the spike protein, so it’s unlikely that a single change would make the vaccine less effective.
Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.
Peacock said, “With this variant there is no evidence that it will evade the vaccination or a human immune response. But if there is an instance of vaccine failure or reinfection then that case should be treated as high priority for genetic sequencing.”
It still allows the virus to replicate and mutate, potentially into a variant that is different enough that the vaccine no longer prevents people from dying.
Coronaviruses like SARS-COV-2 mutate relatively slowly and minimally compared to others. So mutation isn't expected to be a huge concern, unlike say influenza which mutates relatively rapidly and requires an annual tweak to the vaccines.
What's more, any new strains we do see spreading more widely will do so because their mutations confer a competitive advantage. In practice that usually means more drift towards higher infectiousness but less severe symptoms - the same mechanisms that have left us with 4 other endemic but mild common cold coroanviruses.
The new SARS-COV-2 vaccines may be a useful tool to get us over this hump where the virus is still novel to a large proportion of the population, but are unlikely to be required indefinitely.
Current vaccines aren't optimized for the currently dominant Covid strains, they're optimized for the Covid strains that were around a year and a half ago.
Yes, my comment may be on the optimistic side. Although I'm not sure if there are significant signs of mutations right now: AFAIK, the virus from 10 months ago is the pretty much the same virus the vaccine targets today.
Flu changes particularly fast, coronaviruses change much more slowly. However this new covid strain does have some differences in the critical 'spike' bit that vaccines target. They are fairly confident the vaccines will still work. They are doing lab tests to verify. I read somewhere that we'll know more in 2 weeks but I can't remember where I saw that. If the vaccines arent so effective against the new strain, its relatively easy to tweak them (its not like starting from scratch, we know the vaccine approaches work, just need to tweak the payload a little).
My understanding is that with the flu shot scientists and epidemiologists essentially make an educated guess as to which strains are going to be prevalent in a particular year.
Why is COVID-19 different where the expectation is that one vaccine will prove a panacea. The virus has already shown that it can mutate similar to the flu vaccine.
> Over time, as more mutations occur, the vaccine may need to be altered. This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly. The SARS-CoV-2 virus doesn’t mutate as quickly as the flu virus, and the vaccines that have so far proved effective in trials are types that can easily be tweaked if necessary.
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