TY - JOUR
T1 - Historical data and modern methods reveal insights in measles epidemiology
T2 - A retrospective closed cohort study
AU - Paterson, Beverley J.
AU - Kirk, Martyn D.
AU - Cameron, A. Scott
AU - D'este, Catherine
AU - Durrheim, David N.
PY - 2013
Y1 - 2013
N2 - Objectives: Measles was endemic in England during the early 1800s; however, it did not arrive in Australia until 1850 whereas other infectious diseases were known to have arrived much earlier-many with the First Fleet in 1788-leading to the question of why there was a difference. Design: Ships surgeons' logbooks from historical archives, 1829-1882, were retrospectively reviewed for measles outbreak data. Infectious disease modelling techniques were applied to determine whether ships would reach Australia with infectious measles cases. Setting: Historical ship surgeon logbooks of measles outbreaks occurring on journeys from Britain to Australia were examined to provide new insights into measles epidemiology. Primary and secondary outcome measures: Serial intervals and basic reproduction numbers (R0), immunity, outbreak generations, age-distribution, within-family transmission and outbreak lengths for measles within these closed cohorts. Results: Five measles outbreaks were identified (163 cases). The mean serial interval (101 cases) was 12.3 days (95% CI12.1 to 12.5). Measles R0 (95 cases) ranged from 7.7-10.9. Immunity to measles was lowest among children <10 years old (range 37-42%), whereas 94-97% of adults appeared immune. Outbreaks ranged from 4-6 generations and, before 1850, were 41 and 38 days in duration. Two outbreaks after 1850 lasted longer than 70 days and one lasted 32 days. Conclusions: Measles syndrome reporting in a ship surgeon's logs provided remarkable detail on prevaccination measles epidemiology in the closed environment of ship voyages. This study found lower measles R0 and a shorter mean clinical serial interval than is generally reported. Archival ship surgeon log books indicate it was unlikely that measles was introduced into Australia before 1850, owing to high levels of pre-existing immunity in ship passengers, low numbers of travelling children and the journey's length from England to Australia.
AB - Objectives: Measles was endemic in England during the early 1800s; however, it did not arrive in Australia until 1850 whereas other infectious diseases were known to have arrived much earlier-many with the First Fleet in 1788-leading to the question of why there was a difference. Design: Ships surgeons' logbooks from historical archives, 1829-1882, were retrospectively reviewed for measles outbreak data. Infectious disease modelling techniques were applied to determine whether ships would reach Australia with infectious measles cases. Setting: Historical ship surgeon logbooks of measles outbreaks occurring on journeys from Britain to Australia were examined to provide new insights into measles epidemiology. Primary and secondary outcome measures: Serial intervals and basic reproduction numbers (R0), immunity, outbreak generations, age-distribution, within-family transmission and outbreak lengths for measles within these closed cohorts. Results: Five measles outbreaks were identified (163 cases). The mean serial interval (101 cases) was 12.3 days (95% CI12.1 to 12.5). Measles R0 (95 cases) ranged from 7.7-10.9. Immunity to measles was lowest among children <10 years old (range 37-42%), whereas 94-97% of adults appeared immune. Outbreaks ranged from 4-6 generations and, before 1850, were 41 and 38 days in duration. Two outbreaks after 1850 lasted longer than 70 days and one lasted 32 days. Conclusions: Measles syndrome reporting in a ship surgeon's logs provided remarkable detail on prevaccination measles epidemiology in the closed environment of ship voyages. This study found lower measles R0 and a shorter mean clinical serial interval than is generally reported. Archival ship surgeon log books indicate it was unlikely that measles was introduced into Australia before 1850, owing to high levels of pre-existing immunity in ship passengers, low numbers of travelling children and the journey's length from England to Australia.
UR - http://www.scopus.com/inward/record.url?scp=84873548310&partnerID=8YFLogxK
U2 - 10.1136/bmjopen-2012-002033
DO - 10.1136/bmjopen-2012-002033
M3 - Article
SN - 2044-6055
VL - 3
JO - BMJ Open
JF - BMJ Open
IS - 1
M1 - e002033
ER -