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I wonder how much we are seeing general problems with adenovirus vector vaccines (e.g. blood clotting and this manufacturing issue) only because we've never rol
by hardtke 5y ago
I wonder how much we are seeing general problems with adenovirus vector vaccines (e.g. blood clotting and this manufacturing issue) only because we've never rolled a vaccine out to a large population so quickly. Regulatory agencies are likely afraid to approve any at this point, which does not bode well for other vaccines using the same technology.
- ummonk 5y agoIntuitively speaking, using a viral vector has inherent risks that aren’t present with mRNA or protein subunit vaccines. To the extent that the latter technologies prove effective for vaccines against various viruses, I would think viral vectors should not be a preferred technology going forward for vaccine development.
- 627467 5y agoIntuitively, the risks of viral vector vaccines are well known because they have been used for at least a decade while mRNA are being used in large scale for the first time only now.
- Exmoor 5y agoPerhaps previously, but at this point hundreds of millions of people have been injected with mRNA vaccines and the safety profile and efficacy seem much better than any other vaccine technology.
- riffraff 5y agoBut we haven't seen long term effects of mRNA vaccines. I am not expecting a "children of men" distopy, and I'd rather have an mRNA vaccine than any other, but it is possible there might be some unexpected issues in the long run.
- ummonk 5y agoWeren’t the first viral vector vaccines (for Ebola virus) only recently approved? As to track record, the first viral vector vaccines in widespread use (i.e. the COVID vaccines) will have killed hundreds (possibly even thousands) of people via blood clots. That’s a worthwhile trade off for a disease as deadly as COVID. But it would be less acceptable against less dangerous diseases, particularly if safer vaccine technologies are available.
- gus_massa 5y agoThe MMR vaccine contains "live" weakened virus. The kid sometimes get some small red points in the skin that disappear in a few days. The oral polio vaccine "Sabin" has "live" virus. It's stronger than the injectable polio vaccine, but there is a small risk that the virus can escape and mutate and after a year or so cause polio to another person. So countries without polio cases, only use the injectable version "Salk" that does not contain "live" virus. The first smallpox vaccine was just a similar virus for cows. The latest smallpox vaccine also used a "live" virus.
- meepmorp 5y agoNone of those are VVVs, though.
- xvilka 5y agoI am not a virologist, but blood clotting might be related to the specific payload rather than the platform. The original SARS-CoV2 has the same property. Could it be related to the spike protein?
- sanxiyn 5y agoThis preprint suggests AZ vaccine blood clotting is due to EDTA, an ingredient specific to AZ vaccine and absent in other vaccines, and is related to neither platform nor payload. https://www.researchsquare.com/article/rs-440461/v1 https://www.researchsquare.com/article/rs-440461/v1
- meepmorp 5y agoEDTA is an anti-coagulant, though. Blood collection vials are coated with it to prevent clots in blood samples.
- nikolay 5y agoThe adenoviruses themselves are known to cause blood clotting for years and were questioned long ago as being a good vector.
- toast0 5y agoThese are the first widely deployed adenovirus vector vaccine. There have been several rounds of trials of adenovirus vectors vaccines, but they never went forward to widespread use. Viral vector vaccines are a less new concept than mRNA vaccines, so it might be easy to see one as new and the other as traditional, but they're both new.
- perardi 5y agoMy intuition, given the absolute (small) magnitude of blood clots, is that it’s not a huge issue. Except that it is, because it has people spooked. Humans, myself included, are just terrible at gauging relative risk, and it doesn’t really matter that you are way more likely to die in your car driving to get the vaccine than from any vaccine complication. You are putting this in your arm, and people find it scary when even the tiniest issues crop up. (I’ll snark a bit here: wonder how many people who are scared of vaccines smoke cigarettes…because, in terms of risk…hoo boy.)
- Exmoor 5y agoIt's not considering the disease it's protecting against and the currently likelihood of getting it, but if we were talking a flu shot or a vaccine for some much less common disease that math would change.
- nottorp 5y ago> My intuition, given the absolute (small) magnitude of blood clots, is that it’s not a huge issue. Except there are two other vaccines with no risk of bloot clots. So if you can choose, why not choose the ones that aren't linked to that? Ofc, that mostly goes for the US and EU who have secured supply.
- meepmorp 5y agoThe J&J vaccine, at least, is approved for single dose administration. That’s much easier for many people to handle then a 4 week return to someplace for a second round. If you risk getting fired for taking time to get vaccinated, only having to do so once is obviously better.