Finally, some numbers on how well vaccines do in real life

Finally, some numbers on how well vaccines do in real life. By David Evans.

The countries with the highest percentages vaccinated are the UK, USA, and Israel. Real world data on the effect of vaccines is starting to trickle in from those countries.

We know that fully vaccinated people can still catch covid and spread it, but are much less likely to get hospitalized. (For emphasis because this is not what most people assume: the current vaccines are not like most vaccines, which reduce your chance of catching the disease to almost zero.)

How much less likely are they to catch it, spread it, and require hospitalization is partly answered by new Israeli data.

Morgan McFall-Johnsen:

[Israel’s] rapid vaccine rollout was initially successful, bringing the country down to just a handful of new infections per day. But now the rate has climbed back up to roughly 300 new cases per day — largely due to the spread of the Delta variant.

Vaccines have significantly decreased severe illness and deaths in Israel. Even with Delta spreading, the Pfizer vaccine has been 93% effective at preventing hospitalizations, the Health Ministry has reported.

But in preventing infections overall — including mild ones — the vaccine’s efficacy has dropped from 94.3% between May 2 and June 5 to 64% from June 6 to July 3, according to the news site Ynet.

Presumably this means that the number of vaccinated people catching covid is only 64% of the number of unvaccinated people catching covid in the same time period, allowing for the relative numbers of vaccinated and vaccinated people.

About 38% of Israel’s population remains unvaccinated, according to The New York Times’ tracker. Those people are vulnerable to severe illness and death as case counts rise. It’s not yet clear whether vaccinated people with mild infections of the Delta variant can spread it to the unvaccinated.

Already since June, the Israeli government has reinstated an indoor mask mandate and tightened restrictions on travelers from other countries. It’s also announced that vaccinated people may be ordered to quarantine if they’re exposed to the Delta variant.

Still, researchers at the Hebrew University of Jerusalem predicted that the nation could hit 1,000 cases per day in just two weeks if more isn’t done to curb the virus’s spread, according to local media.

Levy told Israeli TV station Channel 12 on Sunday that Israel may need to start limiting large gatherings again — particularly those involving children and unvaccinated people.

“We’re not close to what we’ve seen in the past,” he said, according to The Times of Israel. “It’s nothing like the caseload we had earlier.”

At the peak of its largest COVID-19 surge, earlier this year, the nation reported nearly 12,000 new cases in a single day.

So the Israelis are finding that vaccination of 60% of the population is not enough to completely relax restrictions, and is reapplying some of them.


Cases are still cropping up among the immunized. Last Friday, more than half of the new infections reported were in patients that had been vaccinated, according to Ynet, underscoring the need for further study.

Nikolai Petrovsky, a Flinders University coronavirus vaccine developer and chairman of biotech company Vaxine:

What we consistently see across the board is that all of the current vaccines are not providing the same level of protection against the variants collectively as they did against the original strain.

We don’t want to imply that vaccines are not working because they are still protecting against severe disease. But if we are talking about protection against asymptomatic infection or prevention of transmission, then it is increasingly clear the existing vaccines are not effective in these situations, particularly when they are dealing with the variants.

Of course, just like flu vaccines, we know these vaccines protect mostly against hospitalisation and death. So it should come as no surprise that with Covid-19 we see the same thing.

Currently, the main rationale for vaccinating people against Covid-19 is to reduce the number getting extremely sick, thereby taking the pressure off hospitals. This will remain the case until we have vaccines that can better block infection and transmission than the current generation of vaccines — this is what my own research is directed to.”


  • Vaccines reduce your chances of requiring hospitalization by 95% or so if you do catch covid.
  • Vaccines reduce your chance of catching covid by two thirds in given period (though the British experience, with larger numbers, suggest it is more like an 80% reduction). But if your community has covid then you will be repeatedly exposed — so presumably you may catch covid sooner or later anyway, though as yet there is no data on this.
  • It is not yet clear how much vaccines reduce the probability of spreading the disease to someone else.

Obviously vaccines are a vast improvement over nothing if covid is circulating in your community. However, they are far from perfect and some people will still catch covid, spread it, and require hospitalization — even if everyone is vaccinated. The impact on the incidence of long covid is still unknown. This is not the exit we have been looking for.

Do the benefits of vaccination outweigh the risks? At this stage the answer seems to a definite yes if you are in one of the at-risk groups, namely oldies and fatties. For those under 60 of normal weight, not enough data yet to say.

How does vaccination stack up against say widespread taking of ivermectin? Hard to say, and given the pro-vaccine attitude of authorities, it may be a long time before we get real answers.

How does vaccination stack up against closing borders and not allowing covid to circulate in your community? Pretty poorly. I reckon we need better vaccines before Australia opens its borders to non-essential international travel again.

The nightmare of course is virus escape and something like Marek’s disease, which became 100% fatal in chickens and means chickens now require vaccines. Imagine if our mismanagement steered covid to mutate into 100% fatal, requiring we vaccinate forever.

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hat-tip Stephen Neil