A new study reports 309 lab acquired infections and 16 pathogen lab escapes between 2000 and 2021

In the fall of 2019, workers at a veterinary research center in the northwestern Chinese city of Lanzhou began to fall ill with a disease that caused fever, muscle aches, and other symptoms. Workers at a nearby plant that made brucellosis vaccines had been using expired disinfectant to treat waste gas; the gas was contaminated with aerosolized Brucella bacteria and wafted on southeast winds to the research facility. Eventually over 10,000 people were infected with the disease, which can cause long-term illness. This was just one of 16 times a pathogen escaped from a laboratory setting between 2000 and 2021, according to a new study in The Lancet Microbe.

An international team of researchers looked for all the cases of infections acquired in a laboratory or times a pathogen accidentally “escaped” from a laboratory setting. They found 309 laboratory-acquired or -associated infections from 51 pathogens; eight of these cases were fatal, including one of “mad cow” disease. The 16 incidents they found of a pathogen escaping a lab setting included well-publicized accidents such as the time where a West Nile researcher became infected with the first SARS virus in 2003 after handling contaminated samples in Singapore. He went on to expose 84 contacts and risked re-igniting the 2002-2004 SARS epidemic, by then quiet in Singapore. In another case, US government workers taking inventory in preparation for a move at the National Institutes of Health found old vials labeled “variola,” a reference to the virus that causes smallpox, in an unsecured refrigerator in 2014.

The study comes at a time when the US government and other groups are re-assessing biosecurity protocols for studies involving potentially pandemic agents. Many experts have called for a strengthening of global oversight over pathogen research. The new study on accidents points to one area, where the risks associated with research and biotechnology remain murky: “[Without] globalised formal reporting requirements, the data summarised here could only represent the tip of the iceberg,” the authors wrote.

Overall, North America, Europe, and Asia accounted for most illnesses. More than three-quarters of the reported infections occurred in the United States. Seventy percent of accidents involved procedural errors, which the authors defined as breeches of biosafety or risk mitigation procedures. These could involve the choice of the wrong personal protective equipment, poor training, or the mishandling of samples, including, the authors wrote, by sniffing them. Needlesticks and spills accounted for roughly 15 percent of infections.

About 77 percent of infections involved bacteria, some 14 percent involved viruses, and 7 percent involved parasites. A small percentage of cases invovled fungi or prions, the latter of which can cause bovine spongiform encephalitis or “mad cow” disease. Of the eight fatalities, six were caused by bacteria, including Yersinia pestis, which causes plague; one involved Ebola and the other, a prion.

Incidents in which a pathogen escaped laboratory containment occasionally led to exposures outside of a research facility, but often did not lead to outbreaks (with exceptions like the Lanzhou accident). They involved bacteria, including the anthrax bacteria, and viruses like variola and influenza. Procedural errors (in the case of the Chinese brucellosis outbreak, the use of expired disinfectant) caused most of the escapes.

Studies of laboratory acquired infections date back at least to 1915. That year, a survey turned up 47 infections, many occurring when researchers used their mouths to suck pathogenic material into pipettes, according to a 1966 review of mouth pipetting. Regulations and better practices have reduced some of the risks associated with pathogen work. But continued improvement in biosafety  will be necessary and, many argue, likely require new rules for some research as the world undergoes a boom in construction of labs meant for studying the riskiest of pathogens.