Vaccines looking good for actually doing what vaccines are supposed to do

[dreamshark]

Which is stop the spread of disease. Keeping individuals who have been vaccinated from dying is good too. It's great. But the reason that governments invest so much time and money in broad vaccine campaigns is to stop infection from spreading and to bring epidemics to an end. It has been very disheartening to read so often in recent months that preventing severe disease and death is really "all that matters" and it's just unreasonable to expect the coronavirus vaccine to stop people from spreading the disease. I was pretty sure that there was no evidence to support this most pessimistic of speculations, and now that there is more data coming in, it is appearing that this was indeed the case. A quick Google found this.  I'm sure if you want to look for the detailed studies they are out there somewhere. So...  it's looking good.

Note that the numbers reported for preventing asymptomatic infection are pretty much the same as each vaccine's efficacy at reducing symptomatic infection. So to the extent the vaccines stop you from getting sick, they also stop you from becoming an asymptomatic spreader. More data would be welcome, but early reports are exactly what we want to see. 

Last week, new data from Israel, where nearly 60 percent of the country's 9 million residents have received at least one dose of a vaccine, suggested that the Pfizer-BioNTech vaccine is 94 percent effective at preventing asymptomatic infections.

A separate study conducted by researchers at Cambridge University, in the United Kingdom, found that a single dose of the Pfizer vaccine can reduce asymptomatic infections by 75 percent. The results, which have yet to be peer-reviewed, came from an analysis of around 4,400 tests conducted on vaccinated health care workers in Cambridge over a two-week period in January.

In Johnson & Johnson's trials, the company's vaccine was found to be 74 percent effective against asymptomatic infections. And according to a report released in December by the Food and Drug Administration, early data suggested that Moderna's vaccine may also protect against asymptomatic infections, but the company has said more research is needed. 

Here's a link to another article that describes some of the studies that are planned or under way to nail down the answer to this vital question. Mostly they don't have results yet, but it's interesting to see the different ways of approaching it. Man, that PANTHER study just keeps on giving! Kudos to the University of Nottingham!

Comments

[bibliofile]

I've been thinking of the Covid vaccine as shifting the odds into our favor. That's a miracle enough, in my book. More efficacy the better, but still.

[dreamshark]

The question is, what do we mean by efficacy? Is it preventing sickness or preventing the spread of the infection? As far as I know, this is the first disease where those two things could mean something different. Smallpox wasn't eliminated with a vaccine that turned half the recipients into asymptomatic spreaders - it stopped the infection. If these vaccines don't do something similar we are in deep shit.