Ok… there’s something that’s been bugging me recently.
I keep reading about the rather astounding effectiveness rates of the various COVID vaccines, which are all over 65%, with many over 90%. This is described as effectiveness in preventing serious illness and death in immunized individuals. That’s absolutely fantastic.
But there’s also a set of articles I’ve read that say that the vaccines don’t necessarily prevent transmission of the virus. I’m reading that to mean that if you’ve been immunized and are infected with COVID, that you won’t get sick or die, but that you can still spread the virus.
That gets me to the question at the heart of the thread- is herd immunity even a thing if we can still spread COVID after being immunized? Seems to me that if someone’s un-immunizable for some reason, that they’re at the same risk as they have been all along, as the vaccine isn’t going to prevent anyone from transmitting the disease. Which is kind of the point of herd immunity- once enough people are immune for whatever reason (and no longer spreading the disease), it slows the spread to the point where those vulnerable people are effectively safe because if there is an outbreak, the vast majority of people it encounters are immune, and the outbreak peters out extremely fast.
Is that the case? Am I misunderstanding something and that’s not how it works? Or is it one of those things where the vaccine people are just hedging because they just haven’t tested it yet, and they do expect it to stop transmission as well?
There have been threads and threads on this exact topic. Your snip above is the accurate understanding.
As of the last few days there has come to be emerging evidence that the vaccines do indeed work as expected: They do reduce someone’s likelihood of being infected at all or of passing along the infection, as well as their already known success at reducing or eliminating severe illness in people who become infected.
It’s early days yet, so the error bars are still pretty large on the actual size of this reduced infectivity effect. But it’s definitely a bunch more than “none”.
You have, as LSLGuy notes, grasped the essence of the issue. Given the infectiousness of this virus and because it can spread via completely asymptomatic carriers, obtaining herd immunity in a naive population (e.g. one that isn’t constantly vigilant and using physical isolation and protection measures to reduce the incidence of transmission) will require comprehensive vaccination, and because of the rate mutation and the ability of the virus to host in domestic mammals and potentially spillback, there is still potential for new strains to arise. Certainly the less-than-ideal degree of vaccination that we expect to achieve is going to allow this virus to continue to circulate in some manner indefinitely, potentially requiring seasonal vaccination the way we do for influenza.
What this means is that in addition to vaccination, which many people assume will make the pandemic go away and we can all go back to normal, we should also be taking steps to address the next virulent pathogen whether it is a betacoronavirus or something else like a really infectious and aggressive Influenza A strain. This includes not only building up vaccine testing, production, and deployment infrastructure but also infectious disease surveillance and sequencing, public health education, and modifying our working and social environments to reduce transmission in such ways as reducing door handles and other commonly touched surfaces, making facilities easier to disinfect, and building or modifying HVAC systems to draw air upward and into intakes where it can be filtered and sterilized to prevent superspreading. One thing that has become apparent from this pandemic is just how much poorly ventilated indoor spaces contribute to the transmission of airborne and aerosolized pathogens, and creating better ventilated spaces has numerous benefits (also reducing fungal spores that result in toxic mold, providing well oxygenated air, and the general health and wellness benefits that come of breathing fresh air).
We also need to rethink the necessity of frequent air travel; aside from the climate impacts and other environmental costs, it also poses a difficult-to-track route for epidemic outbreak. And we clearly need to think more about what and who are ‘essential’ in our economy and have a think toward providing them both better protections and living wage guarantees instead of assuming that there is always an infinite pool of medical personnel and first responders, meatpackers, grocery store workers, et cetera.
The medical community ate much crow in the early stages of COVID and are being much more cautious now. They aren’t even guaranteeing the vaccine will immunize you for more than 90 days at this point.
I think just about everyone believes it will but they are being very careful to stick to claims made on evidence this time around.
Door handles? Is that why they live longer in Japan?
When a big disaster occurs, the long-term reaction tends to be over-reaction. Appeasement was a mistake with Germany, but it isn’t always a mistake. There also was overreaction after 9/11, and again recently with barbed wire around the Capitol.
Should there be government grants to study other possible mRNA vaccines? Sure. It’s all a matter of degree, and of not expecting the next pathogen to be all that similar. I’d like to see more serious attention to requiring childhood vaccination, since most viruses don’t skew towards the elderly.
I fear the overreaction will be in the direction that is politically easy (door handles) rather than important (high vaccination rate; infectious disease tracing).
And apologies for fastening on one little part of your good post that it easy to go after (door handles).
Just to add to the responses above, one of the themes in prior misunderstandings of this issue was along the lines of: What? But stopping the spread is just as important! Why haven’t scientists prioritized this in developing vaccines!
In fact, stopping disease and stopping spread are not in any sense mutually exclusive targets. Quite the reverse, any vaccine that effectively induces our immune system to nuke a pathogen quickly is likely to achieve both objectives to at least some degree.
But think about how the trials work. It’s very easy to measure how many people are getting sick in the vaccinated group vs the control group. But these people are not sitting in a lab, they are out living their lives as normal. How would you go about measuring how many other people in the world at large were being infected by the test subjects?
So the fact is, it’s just much more difficult to obtain reliable data on whether vaccination provides sterilizing immunity, whether its prevents spread from vaccinated people to other people. That’s why researchers have been careful to remind people that “we don’t know if it works” - which of course gets distorted by ignorant journalists into a scary implication that “we know it doesn’t work!”
It was always a sensible a priori expectation that vaccination would stop transmission to some degree.
Could you please expand on what you mean here? When you say ‘given the infectiousness of this virus’, do you mean it’s a little infectious or a lot infectious? You seem to imply that ‘herd immunity’ won’t or can’t be reached without vaccination, so I want to read the first part of your sentence as claiming that the virus has characteristics that won’t allow it to reach enough hosts on its own. But high infectiousness – which I kinda thought the virus was deemed to have – and asymptomatic spread would seem to point in the opposite direction. Kinda hard to parse out the logic in this sentence.
Also, are you using ‘naive’ in some sort of colloquial or non-scientific way there? It is my understanding that ‘naive population’ has a specific scientific meaning of its own in this context, and that it’s not the one you gave.
That’s kind of an odd comment. mRNA vaccines aren’t particularly suited to coronaviruses. The whole awesome thing about them is being able to crank it out fast given a suitable protein target on the virus.
Door handles, light switches, and other surfaces are common exchanges for many disease that spread primarily via fomite transmission. Notice how modern public bathrooms eschew knobs or levers for toilets, faucets, and even soap and paper dispensers. The same principle applies, and for the most commonly used entrance doors there is little reason to not automate their functions (with a manual release, of course, in case power goes out). This is not a novel concept, and it is “politically easy” things like this that can reduce transmissibility, which in no way precludes taking other effective measures to strengthen disease surveillance and vaccine production/distribution capabilities.
When COVID first came to attention, not much was known, and there were two obvious possibilities: it killed everyone who was infected, but didn’t infect many people, or, it infected everyone, but didn’t kill many.
Going with the first option, contact infection was the means of spread. Because if non-contact infection was possible, everyone would get COVID, and we would all die, which was not the observable situation.
However, it is now known that most people who get COVID do not die, the number of infections is much greater than the number of deaths, the majority of infection is non-contact infection, and consequently, door knobs are much less important in the COVID epidemic than first feared.
Door handles and other touch surfaces are less important to this pathogen. For something than is transmissible via body fluids such as Ebola, however, it is far more of a concern. We need to be thinking on not just what to do to protect against this pathogen but what can be done to protect against contagion in general.