Affordable Access

Access to the full text

Symptoms and laboratory manifestations of mild COVID-19 in a repatriated cruise ship cohort

  • Bailie, C. R.1, 2, 3
  • Franklin, L.1
  • Nicholson, S.4
  • Mordant, F.5
  • Alpren, C.1
  • Stewart, T.6
  • Barnes, C.1
  • Fox, A.2, 5, 5
  • Druce, J.4
  • Subbarao, K.2, 5
  • Catton, M.4, 5
  • van Diemen, A.7
  • Sullivan, S. G.1, 2, 5
  • 1 Communicable Diseases Epidemiology and Surveillance, Australia , (Australia)
  • 2 WHO Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, At the Peter Doherty Institute for Infection and Immunity, Australia , (Australia)
  • 3 National Centre for Epidemiology and Public Health, Australian National University, Australia , (Australia)
  • 4 Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital, At the Peter Doherty Institute for Infection and Immunity, Australia , (Australia)
  • 5 University of Melbourne, At the Peter Doherty Institute for Infection and Immunity, Australia , (Australia)
  • 6 National Incident Room, Commonwealth Department of Health, Australia , (Australia)
  • 7 Health Protection Branch, Victorian Department of Health and Human Services, Australia , (Australia)
Published Article
Epidemiology and Infection
Cambridge University Press
Publication Date
Feb 10, 2021
DOI: 10.1017/S0950268821000315
PMID: 33563349
PMCID: PMC7900670
PubMed Central


Much of our current understanding about novel coronavirus disease 2019 (COVID-19) comes from hospitalised patients. However, the spectrum of mild and subclinical disease has implications for population-level screening and control. Forty-nine participants were recruited from a group of 99 adults repatriated from a cruise ship with a high incidence of COVID-19. Respiratory and rectal swabs were tested by polymerase chain reaction (PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Sera were tested for anti-SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) and microneutralisation assay. Symptoms, viral shedding and antibody response were examined. Forty-five participants (92%) were considered cases based on either positive PCR or positive ELISA for immunoglobulin G. Forty-two percent of cases were asymptomatic. Only 15% of symptomatic cases reported fever. Serial respiratory and rectal swabs were positive for 10% and 5% of participants respectively about 3 weeks after median symptom onset. Cycle threshold values were high (range 31–45). Attempts to isolate live virus were unsuccessful. The presence of symptoms was not associated with demographics, comorbidities or antibody response. In closed settings, incidence of COVID-19 could be almost double that suggested by symptom-based screening. Serology may be useful in diagnosis of mild disease and in aiding public health investigations.

Report this publication


Seen <100 times