Breakthrough vaccine?

More good news, this time from the Oxford vaccine. The trials are at an earlier stage (phase 2/3) so there are no efficacy numbers yet, but these data show a good immune response, and similar across all age groups including the elderly participants.

This is an adenovirus-vectored vaccine. It uses the same antigen, the Spike protein, and its manner of action is somewhat similar to the mRNA vaccines. Rather than injecting the antigen itself, the engineered adenovirus vector enters your cells and causes your own cells to make the Spike protein, triggering the immune response. But unlike the mRNA vaccines, adenovirus is DNA, so the DNA > mRNA > protein production process all takes place inside your cell, rather than injecting mRNA directly.

Lancet report:


Very encouraging stuff from Derek Lowe yesterday at his "In the Pipeline" blog.

  • How long will the vaccine protection last?
    • Bottom line: Taken together, this study, several others over the past few months, and this recent work all paint a consistent picture of a strong, normal, lasting immune response in the great majority of patients. Add in the results we’re seeing from the two vaccines that have reported interim data so far, and I think that the prospects for lasting immunity from vaccination are also very good . Remember, the early vaccine data suggested antibody responses at least as strong as those found in naturally infected cases. There seems (so far) every reason to think that vaccine-based immunity will be as good or better than that conferred by actual coronavirus infection. I very much look forward to more data to shore up this conclusion, but that’s how it looks to me at the moment.
  • How effective are these vaccines? Will they provide total protection or not?
    • Bottom line: the results we have so far indicate that these vaccines will indeed provide strong protection in the great majority of patients . The number of asymptomatic cases among the vaccinated population will be a harder number to pin down, but I believe that we should be in good enough shape there as well, based on antibody levels in the primate studies and what we’re seeing in humans.
  • What about coronavirus mutations? Will the virus move out from under the vaccine’s targeting?
    • Bottom line: the coronavirus can’t undergo the wholesale changes that we see with the influenza viruses. And the mutations we’re seeing so far appear to still be under the umbrella of the antibody protection we’ll be raising with vaccination, which argues that it’s difficult to escape it.
  • What about efficacy in different groups of people? Where will the vaccines work the best, and where might there be gaps?
    • Bottom line: our first look at efficacy in older patients is very good indeed, and that’s the most significant high-risk patient subgroup taken care of right off the top.
  • How safe are these vaccines? What do we know about side effects?
    • Bottom line: immediate safety looks good so far. Rare side effects and long-term ones are still possible, but based on what we’ve seen with other vaccines, they do not look to be anywhere at all significant compared to the pandemic we have in front of us.
  • OK, what about the rollout? Who’s getting these things first? When does everyone else get a chance to line up?
    • Bottom line: the very first people to get these new vaccines will almost surely be health care workers, and starting some time on in December. The rollout after that has too many variables to usefully predict, but it’s going to be the biggest thing of its type ever attempted, in people-per-unit-time. And yes, I think it’s going to work, and not a minute too soon.

Have we gotten more data on this? It seems like I originally read that the vaccine was tested on whether or not vaccinated persons got sick and that there was no confirmation that vaccinated persons couldn’t still spread the disease, even if they themselves didn’t get sick. Am I incorrect on that or just wrong? Or was that just a CYA type of thing because it wasn’t explicitly tested for, but there’s a general expectation that it prevents transmission?

Can someone that doesn’t have the virus spread it?
I mean, yeah, if I’m immune and a sick person sneezed on something, which I touched and then passed those germs to an un-immune person, sure, but I don’t think that’s what you’re talking about.

I assume you mean, if I’m immune, and inhaled enough droplets from a sick person that would otherwise get me sick, could I pass that off to someone else? That, I have no idea about. I suppose (but have no idea at all) that maybe there’s some window between the time the virus is incubating and the time my anti-bodies kill it, that it could be passed to someone else.
Even if there aren’t studies done on that, I’m guessing it’s either something that the scientists can make a reasonable guess on based on other viruses. If not, we’ll probably know soon enough. Especially in cases where vaccinated medical workers still end up with sick family members (where the medical person is the only person in the family known to be in contact with anyone sick).

Interesting question though. Hopefully the answer is no, a vaccinated person can’t transmit/carry the virus to other people.
Is this a thing with other vaccines? For example, can people that get the flu vaccine and don’t get sick with the flu, still transmit it to others?

What has been tested is “do vaccinated people get symptoms”, because it’s way easier to ask your test subjects to enter data about how they feel into an app than it is to test them every week (or whatever).

So we don’t know these vaccines prevent transmission. Hypothetically, vaccinated people could be asympomatic but spewing virus. It’s pretty unlikely, though. Early testing showed that these vaccines prompted a neutralizing immune response that should keep the virus from replicating much. And that’s probably why vaccinated people are less likely to get sick. It seems very unlikely that the virus doesn’t actually prevent the virus from replicating but does prevent symptoms in some mysterious other way.

Yes, it does happen sometimes, and scientists can make a reasonable guess that it won’t happen very often. Partly because it doesn’t happen very often with other infectious diseases, partly because it’s already known that asymptomatic COVID carriers are less likely to pass on infection than symptomatic or pre-symptomatic carriers, and partly because the vaccines seem to be giving a very good level of immunity.

On the other hand, damn, it seems like this virus, rarely, can be very, very sneaky, and leak out through the smallest quantity. So expecting vaccination to be 100.00000% effective in preventing transmission, even in the 95% of the cases where it gives good immunity, will not be something you can scientifically expect.

If you have a million immune people exposed to COVID, as their bodies react, some of them are still going be shedding enough virus to infect somebody.