The potential impact of a recent measles epidemic on COVID-19 in Samoa

Abstract

Background The pandemic of COVID-19 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 causes an immune amnesia which can persist for over 2 years after acute infection and increases the risk of a range of other infections. Methods We modelled the potential impact of measles-induced immune amnesia on a COVID-19 epidemic in Samoa using data on measles incidence in 2018–2019, population data and a hypothetical COVID-19 epidemic. Results 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 is 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%. Conclusions Samoa, which had large measles epidemics in 2019–2020 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.

Uo mo aso uma, a o uso mo aso vale: Lessons from Aotearoa physiotherapists responding to disasters within the Pacific

“…The subsequent measles epidemic that occurred in Samoa caused a state of emergency to be declared on 15 November 2019, which was withdrawn towards the end of December 2019. It infected over 5,700 Samoans (up to 3% of the population) and claimed 83 lives (Macintyre et al, 2020;World Health Organization, 2020). The majority (87%) of these fatalities were children under the age of four years (Craig, Heywood, & Worth, 2020;Duckor-Jones, 2020).…”