As I related here a couple of weeks ago, I brought forward my second dose of the AstraZeneca vaccine to 9 weeks after the first dose1. While partial protection against Covid-19 can occur as soon as 12 days after the first dose, this protection is likely to be short-lived. After the second dose, it takes from 7 to 14 days, after which any individual should be fully protected2. I reach that 14 day mark on Wednesday (September 15). I am slightly relieved given the mess that New South Wales is in currently, but I realise that it does not stop me from contracting Covid-19. However, studies suggest that the AstraZeneca vaccine prevents 80% of infections, as does the Pfizer vaccine. In addition, if vaccinated people do become infected, they tend to have milder symptoms. Currently, in the US, 97% of the people hospitalised with Covid-19 are unvaccinated3. Given that 53% of the entire US population has had two doses of the vaccine, and 9% have had one dose4, it is pretty impressive that almost all hospitalised people come from less than half the population.
I also realise that if I contract Covid-19, being vaccinated does not stop me spreading the virus. A study in the UK of how Covid-19 spread through over 350,000 households showed that if a person became infected after being vaccinated, they were only half as likely to pass the virus onto those in the household, than if they were unvaccinated. However, that was before the Delta strain emerged; this is the dominant strain in Australia today. A US study has suggested that if a vaccinated person is infected with the Delta strain, they will pass the virus on just as readily as people who haven’t been vaccinated3.
Despite the effectiveness of the vaccines, I still have as little contact with others as possible (we are in lockdown after all), only going out to get food and plonk. When I do go out, I always wear a mask (it is mandatory). And the mask is not so much to stop me contracting Covid-19, but to stop me passing it onto others. After all, because I am fully vaccinated, I may have Covid-19 and be asymptomatic, and a risk to others. By wearing a mask, it is them I am trying to protect, as I expect others to do to try to protect me.