Lara Herrero for The Conversation
When a COVID cluster includes people who are vaccinated against the virus’ we inevitably hear rumblings of complaint from people who wonder what the point is of vaccination.
But when you read past the headlines’ you usually see the answer: in most cases’ those who were vaccinated and contracted COVID-19 didn’t die’ didn’t develop severe symptoms and didn’t need to be hospitalised.
For unvaccinated Australians in their later years’ the chance of dying from COVID is high. For unvaccinated people in their 80s’ around 32 percent who contract COVID will die from it. For people in their 70s’ it’s around 14 percent . (For unvaccinated people in their 60s’ it drops to around 3 percent . And for under-50s’ it’s less than 1 percent .)
The good news is both Pfizer and AstraZeneca are very effective at preventing severe disease and death from COVID-19′ even from the more virulent Delta strain.
So how effective are our vaccines?
Preliminary data from the United Kingdom shows after your first dose of either Pfizer or AstraZeneca’ you’re 33 percent less likely than an unvaccinated person to contract the Delta variant.
Two weeks after your second dose’ this rises to 60 percent for AstraZeneca and 88 percent for Pfizer. This data is for any form of COVID-19′ from mild to severe.
But when you look at how much the vaccines reduce your risk of developing severe illness that requires hospitalisation’ the coverage is high for both. Pfizer and Astrazeneca vaccines are 96 percent and 92 percent effective (respectively) in preventing Delta variant hospitalisations.
Why do some people still get COVID after being vaccinated?
Vaccines aren’t magic barriers. They don’t kill the virus or pathogen they target.
Rather’ vaccines stimulate a person’s immune system to create antibodies. These antibodies are specific against the virus or pathogen for the vaccine and allows the body to fight infection before it takes hold and causes severe disease.
However’ some people won’t have a strong enough immune response to the vaccine and may still be susceptible to developing COVID-19 if exposed to the virus.
How a person responds to a vaccine is impacted by a number of host factors’ including our age’ gender’ medications’ diet’ exercise’ health and stress levels.
It’s not easy to tell who hasn’t developed a strong enough immune response to the vaccine. Measuring a person’s immune response to a vaccine is not simple and requires detailed laboratory tests.