1788 First Fleet Likely Introduced Smallpox to Australia, Study Finds

A mathematical modeling study published July 9 in the journal Nature Human Behaviour indicates that the 1789 smallpox outbreak among Indigenous Australians was likely triggered by the British “First Fleet.” Researchers found that vials of dried smallpox scabs carried by British medics for inoculations were the probable source of the disease, which caused an estimated 220,000 deaths.

The study, co-authored by Alan Williams of EMM Consulting and Matthew Cody Nitschke of Flinders University, uses computer modeling to refute a long-standing theory that the virus entered the continent via Indonesian islanders in the north. According to the researchers, the disease’s spread pattern points to an origin near Port Jackson in the southeast.

The First Fleet arrived in 1788 with 11 ships, including naval vessels, convict transports, and provision ships. While no smallpox cases were recorded on the fleet during the voyage, the researchers argue the virus was present in the form of scabs used for inoculation—a practice that preceded Edward Jenner’s development of the smallpox vaccine in the 1790s.

Some historians previously argued the live virus could not survive the eight-month journey from Portsmouth, England, to Botany Bay. However, Williams told Live Science that the vials may have been replenished during stops in Rio de Janeiro, Brazil, or Cape Town, South Africa, just months before arriving in Australia.

Why the North Coast Theory Was Rejected

For years, the absence of recorded cases on the First Fleet led some to believe the outbreak began on the tropical north coast through contact with fishers from the Makassar region of Sulawesi, now part of Indonesia. The new modeling data contradicts this possibility.

Nitschke told Live Science that the evidence strongly supports the First Fleet as the source and suggests it is very unlikely the outbreak originated in the north. Williams noted that the north coast and the southeast are separated by thousands of miles of uninhabited desert, which would have prevented the disease from spreading to the regions where the outbreak was most concentrated.

Conversely, the modeling of Indigenous communities near Port Jackson shows the outbreak originated in that specific area. Williams added that because disease theory was not understood at the time, the spread likely occurred by accident.

Revised Indigenous Population Estimates

The research in Nature Human Behaviour refers to a second upcoming study by the same team that challenges historical population data. Earlier studies from the 1930s estimated the Indigenous population at roughly 300,000 people at the time of British arrival.

The new research proposes that there were up to 3 million Indigenous Australians in 1788. Based on archaeological investigations of early communities, the researchers suggest the theoretical population capacity of the continent was as high as 5 million people, particularly in resource-rich areas of the North and Southeast.

Williams explained that the 1930s estimate was flawed because it relied on depleted numbers recorded after a century of disease and frontier violence. He stated that early 20th-century authorities did not comprehend the actual scale of the population they were documenting.

Expert Analysis of the Findings

Independent historians have supported the study’s conclusions. Henry Reynolds, a historian at the University of Tasmania, told Live Science that the research debunks the north coast theory, calling the idea that the disease arrived from the north at the exact time as the First Fleet improbable.

Ann McGrath, a historian at the Australian National University in Canberra, stated in an email that the interdisciplinary approach of the research convincingly refutes the previous theories and provides a significantly expanded estimate of the pre-1788 Indigenous population.

The study concludes that the resulting smallpox outbreak contributed to the rapid demise of Indigenous Australian culture and devastated communities across the continent.