The U.K. launched the word’s first mass COVID-19 vaccination on 8 December 2020. John Ng and Scott Reid, as part of their work in the IFoA Covid-19 Action Taskforce, explore whether the data supports early signs of immunity build up and mortality impact on people 80 years of age and above in England.
By applying actuarial and data science techniques they explore, through counterfactual “unvaccinated” scenarios, key insights into actual versus expected mortality for age 80 year of age and above. Techniques applied include Gompertz function, linear regression and machine learning where historical observation showed that the mortality in younger age groups are great predictors of the mortality in older 80 years of age and above group.
The models showed statistically significant mortality reduction from middle of January onwards:
- Registered deaths show an estimated reduction of 32% up to 12 February; and
- Hospital deaths show consecutive mortality reductions for many weeks and arrived at an estimated 50% reduction by 20 February.
The timing of mortality reduction is compatible with the increase in prevalence of community antibody positivity among the 80+ age group according to data published by the Office of National Statistics.