ATLANTA, Ga. — To date, there are more than 18 million confirmed cases of COVID-19 around the world. The virus has spread to every corner of the globe throughout 2020 and tragically caused nearly 700,000 deaths. So how did things get so bad? A new study finds the first cases in at least two-thirds of infected nations are linked to travel involving China, Italy, and Iran.
The U.S. Centers for Disease Control and Prevention says an examination of COVID-19 records during the first 11 weeks of the outbreak reveals a strong connection to the pandemic spreading out of these countries. From Dec. 31, 2019 to March 10, 2020, the first case of coronavirus in 75 of 99 affected nations (outside of China) involves a person traveling to an area where the virus was already spreading.
“Our findings suggest that travel from just a few countries with substantial SARS-CoV-2 transmission may have seeded additional outbreaks around the world,” says the CDC’s Dr. Fatimah Dawood in a media release.
Travel’s devastating role in the pandemic
The CDC says this is the first study looking at how international travel spread COVID-19 before the outbreak was officially declared a pandemic. Over 32,000 cases in 99 countries outside of mainland China were recorded during the first 11 weeks of 2020.
Travel to Italy in particular had a devastating impact on several continents and the countries within. Three of the six first cases in Africa have ties to Italy. Over a third — 16 of 45 nations — in Europe and nearly 40 percent of countries in the Americas link initial infections to Italy.
Exposures linked to mainland China account for nearly all of the first cases in the Western Pacific — 10 out of 12 countries. The Chinese city of Wuhan is suspected of being the origin point for SARS-CoV-2, the virus which causes COVID-19.
The scientists also link 44 percent of first cases in the Eastern Mediterranean to travel to and from Iran.
Where did people spread COVID-19?
The CDC team says they have in-depth data on 1,200 of the initial coronavirus cases from 68 different countries. From that information, they are creating a picture of how and where the virus was spread in January, February, and March.
Among these early cases, the average age of a COVID-19 patient is 51. Just three percent are younger than 18 years-old and only two percent of the patients are healthcare workers.
During this pre-pandemic period, the CDC study shows the virus was most commonly passed on to others inside a household. These transmissions get an average of 2.6 people sick. The report also reveals faith-based groups and dinner parties played the biggest role in widespread transmission of COVID-19. An average of over 14 people were diagnosed with coronavirus after attending one of these gatherings.
“Four large clusters in our analysis, and large outbreaks reported elsewhere, have been linked with transmission in faith-based settings, highlighting the need to partner with faith-based organizations when designing and implementing community mitigation efforts,” says co-author Dr. Philip Ricks.
Dr. Ricks also points to several infection clusters in medical facilities, underscoring the need for better infection prevention practices inside hospitals.
The picture remains incomplete
The CDC says their report doesn’t paint the entire picture of the pandemic because of limited data from low-income countries. Only six out of 46 countries in and around Africa had reported COVID-19 cases by the time the World Health Organization declared COVID-19 a pandemic.
“Accurate data from these settings will be needed to assess the full global effect of the COVID-19 pandemic,” Dawood explains.
The study appears in The Lancet Infectious Diseases journal.