In the past couple of weeks, Renata and I have been asked “Have you been vaccinated?” by several different people. Now I don’t mind saying yes – but I’m not sure that the question really is what it sounds like. I think the question is “Can we visit your place with certainty that we won’t catch covid?” Perhaps the question is “Have you been immunized?”
Vaccinated and immune have two different meanings. The history of smallpox vaccination shows the differences over a thousand-year timeline. The first vaccinations recorded are in China, after 1000 CE. They’d grind up the scabs from someone with smallpox, and blow the dust into your nostrils – along with something like a 2% mortality rate. Since the death rate from smallpox was about 30%, it seemed like a decent risk. This practice was variolation, not vaccination.
This development was state of the art until Jennings developed vaccination about 800 years later. You remember, he took matter from the sores on a cow that had cowpox and injected it into people. The latin word for cow – vacca – became the root of the word “vaccination.” Since cowpox wasn’t smallpox, it took the risk of death down to about zero – but the minimal controls of the early 19th century kept the effectiveness down. Jennings methodology didn’t guarantee the inoculation actually included cowpox. Even as smallpox was eradicated, the vaccine was only 95% effective – but a 95% effective vaccine wiped out smallpox.
Life is a game of percentages – the only certainty is death . . . but we don’t know when. When my colon cancer was diagnosed in May, 2009, the prediction was June, 2012. The prediction changed when Rick Holm convinced his colleagues to humor me and look at the 2002 chest X-rays. Just old scars, no new metastasis. It changed the diagnosis from stage 4 to early stage 3. All from looking at one 7 year-old X-ray.
CDC says my two doses of Pfizer should be 84% effective. Israel’s health ministry rates it at 39%. Personally, even 39% effective is worth getting the vaccine – I have made a point of getting flu shots that were no more effective. But the answer to “Have you been vaccinated?” isn’t really a simple yes or no if the question is actually “Have you been immunized?”
I think my friends are happier visiting with the knowledge I’ve been vaccinated, and not knowing the percentage effectiveness. Vaccinated generally translates to less chance of getting sick – but few vaccines are 100% effective. The recent infectiousness of this last covid outbreak has demonstrated that vaccination is not synonymous with immunization.