The COVID-19 pandemic has occurred close on the heels of a global resurgence of measles. In 2019, an unprecedented epidemic of measles affected Samoa, requiring a state of emergency to be declared. Measles is known to cause immune amnesia, which can persist for over 2 years after acute infection and increases the risk of a range of other infections. The objective of this modelling study was to estimate COVID-19 impact in Samoa, taking into consideration the increased risk of infections resulting from temporary immune amnesia from Measles.
The young population structure and contact matrix in Samoa results in the most transmission occurring in young people < 20 years old. The highest rate of death occurs among the 60+ years old, but a smaller peak in death may occur in younger people, with more than 15% of total deaths in the age group under 20 years old. Measles induced immune amnesia could increase the total number of cases by 8% and deaths by more than 2%.
Samoa should focus on rapidly achieving high rates of measles vaccination and enhanced surveillance for COVID-19, as the impact may be more severe due to measles-induced immune paresis. This applies to other severely measles-affected countries in the Pacific, Europe and elsewhere.View paper