The majority of studies show elderly persons (>65 years) have significantly longer COVID-19 incubation periods compared to younger adults with a mean difference of +3.9 days (Lieu J et al. 2020; Kong TK et al. 2020; Jiang et al. 2020; Guo et al. 2020). One study showed no difference between those >60 years and younger patients (Lian et al. 2020).
Median incubation period across all studies (all ages) was 5 days (5.4 days mean). Jiang et al. (2020) report a mean incubation period of 7 days for younger adults and 10.9 days for those over age 65.
Upper limit of incubation period is 12-14 days with one study reporting 27 days (Nanda et al. 2020).
Median duration from symptom onset to death is 11.5 days in persons >70 years vs. 14 days in younger adults (Geriatric Emergency department collaborative March 2020).
Older age and more severe infections are associated with higher viral loads; however, viral shedding is not associated with infectivity. (European Centre for Disease Prevention and Control, 2020).
Doubling time of COVID-19 among residents from a single long-term care home was estimated to be 3.4 days compared to 5.5 days in the general population in the surrounding county (Arons et al. 2020).
Infected patients over the age of 65 years remain contagious for a significantly longer period (22 days vs. 19 days, p=0.015; Ziao et al. 2020).
Viral shedding may be longer for immune compromised patients (BC CDC 2020).
Symptom duration varies by nature of the symptom with a median time from diagnosis to discharge from hospital ranging from 13 days (range = 7-17; Ki et al. 2020) to 18.5 days (range = 11-27; Kim et al. 2020).
There is limited information on basic reproduction number in older adult populations. These values vary by region and over time. R0 values for whole populations (all ages) have been reported as low as 0.48 (Ki et al. 2020) to 2.5 (Lewnard et al. 2020)
Please see related reports by the Laboratory Working Group available in the SHA COVID-19 repository (not specific to elderly).
o LAB041601 RR Antibody development, viral shedding and infectiousness.
o LAB040701-01 RR Proportion of disease transmission due to asymptomatic, pre-symptomatic and symptomatic cases.
Tupper, S; Ward, H; Dalidowicz, M; Ellsworth, C. What is the incubation period, rate of spread, and duration of infectivity of COVID-19 in older adults? 2020 Jun 19; Document no.: LTC060202 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 28 p. (CEST rapid review report)