Evolving Evidence Does Not Support Zero Covid as a Strategy

Written by Dr Tim Trodd

The long term effectiveness of vaccines is going to be a key factor in how countries deal with Covid over the coming years. We have described previously that Zero Covid is not a sustainable strategy. As the virus becomes endemic it is likely that all humans will, sooner or later, be exposed. In this case, the relative immunity offered by the vaccine versus that caused by catching the disease itself becomes important information. A recently published study from Israel shines some light on this.

The team compared the likelihood of subsequent infection with the Delta strain of the Covid virus amongst people who had a) the disease in January and February 2021 or b) the BioNTech vaccine in January and February 2021. They found a 13-fold increase in infection overall in the vaccinated group and a 27-fold increase in symptomatic infection in the vaccinated group versus the previously infected group. This strongly suggests that previous natural Covid infection is better protection against Delta Covid than BioNTech vaccination. They also demonstrated additional protection from both having the disease and also being vaccinated. The immunity given by both the vaccine and disease waned over time.

This suggests that vaccination of the vulnerable and managed disease will produce a better long term outcome than a vaccination and a Zero Covid policy.