GSK, the pharmaceutical company, has inaugurated a new BSL-4 biosecurity laboratory at its research facility in Tres Cantos, about half an hour from Madrid. This is the first of its kind in Spain and the first for a global pharmaceutical company, operated by a team of seven researchers, five of whom are women.
Five out of the 27 BSL-3 rooms previously operational in the facility have been converted into two rooms meeting BSL-4 requirements, enabling the handling of the most dangerous known pathogens that cause severe or fatal diseases, for which no vaccines or effective treatments are currently available, such as the Ebola and Marburg viruses. David Barros, Head of Research and Development for Global Health at GSK in Spain, emphasized that "the difference between BSL-3 and BSL-4 is not merely technical, but existential as well," noting that in BSL-3, treatment options may exist, whereas BSL-4 pathogens do not have known prevention or treatment.
The decision to establish the laboratory was influenced by the global COVID-19 pandemic, when the Tres Cantos center, specializing in infectious diseases, focused its efforts on the virus. Barros states that the pandemic sparked a desire among some researchers to have such a laboratory, and it seemed almost a duty to them.
The center, with over thirty years of history and nearly one hundred researchers dedicated to discovering drugs for vulnerable populations, primarily addresses "neglected" diseases like malaria, tuberculosis, and antibiotic resistance. Among its previous achievements is tafenoquine, a single-dose treatment for a type of malaria that can remain dormant in the liver, and the discovery of bacteria that colonize mosquito intestines and prevent them from transmitting the malaria parasite.
The cost of converting certain rooms to BSL-4 level was approximately €5.2 million, and GSK benefitted from previously trained researchers and a thirty-year track record with no incidents at BSL-3 facilities, according to the company.
Before commencing operations, the company posed a practical question: how many researchers are willing to take the risks involved with pathogens classified as BSL-4? The precise definition of these pathogens is that they can cause severe or lethal diseases with no effective treatment or vaccine available to date. The team in Tres Cantos is initially focusing on multidrug-resistant tuberculosis—which current treatments fail against in approximately half a million people worldwide each year—and Crimean-Congo hemorrhagic fever, a tick-borne viral disease endemic to the Balkans, which lacks approved vaccines or antiviral treatments and has a "high epidemic potential," according to Barros.
Seven researchers responded to the offer and underwent specialized training in Spain and the UK for utilizing BSL-4 facilities. The entry procedures to the laboratory are extremely stringent: all clothing must be removed in designated changing rooms, followed by a shower and donning laboratory attire, with contingency for backup goggles if available. Researchers enter in pairs and work in a "mirror" system, with each assessing the other's readiness before granting permission to enter after a series of questions and tests.
The researchers wear full-body positive-pressure suits commonly referred to as "space suits," which include independent oxygen supply and airtight seals. The process of donning and doffing the suit takes time, and the entire entry, working, and decontamination process before exiting can take up to an hour and a half, with a practical maximum working time inside the room generally limited to four hours. The procedures do not allow for quick breaks or exiting for water or bathroom needs while inside.
Technically, BSL-4 is an enhanced version of BSL-3 standards: there are redundant and fortified systems to prevent any leaks. In addition to filtering air out of the lab, incoming air is filtered four times using the strongest available filters, and waste is sterilized twice within the facility before leaving. Negative pressure systems ensure that air always flows in and does not escape even in case of power interruptions, thanks to back-up systems. Transport between work areas is conducted through airtight containers to avoid opening doors carrying the most dangerous materials. All BSL-4 protocols include built-in alternative plans.
The GSK facility has two independent rooms functioning as separate BSL-4 labs, so each room can host a different pathogen and operate completely independently, according to Javier Gamo, Global Health Research and Medicines Industry Director at GSK.
The company assures that safety is the foremost priority, with oversight authorities able to conduct surprise inspections at any time. The Global BioLabs 2023 report from King’s College London notes that 51 BSL-4 laboratories operate across 27 countries, with only eight institutions housing these labs within the European Union. The report also states that three-quarters of BSL-4 laboratories are located in urban areas, increasing potential risks in the event of a leak.
Spanish authorities are also expanding construction of a government BSL-4 laboratory within the Carlos III Institute in Majadahonda, expected to come online next year. They have signed a cooperation agreement with GSK, and Pedro Sánchez visited the Tres Cantos laboratory on March 3.
The GSK lab in Tres Cantos has received the Comunidad de Madrid certification, with internal verification and accreditation processes to be completed in April. Following this, the team will gradually work at lower levels (2 and 3) before fully transitioning to Level 4, expected to be completed between late 2026 and early 2027. Researchers will undergo rigorous periodic health monitoring, training for months on entry and exit protocols, and will repeatedly execute the protocols until they become second nature, before one enters a lab with a real pathogen for the first time.