Close up image of a flu virus  ©

Bjorn Meyer


Flu epidemics globally lead to at least five million severe cases every year and as many as half a million deaths. Whenever someone we know succumbs to the flu virus we assume they will do everything they can, not to pass it on to others. Healthcare workers need to protect themselves from exposure.  And what if we need to expose ourselves to the virus to find out how it is transmitted? Influenza specialist Professor Jonathan Van-Tam at Nottingham University is seeking an answer to the vexing question: ‘how is influenza transmitted and should healthcare staff wear a mask or respirators?’


Since 2008 Van-Tam has led an international consortium to coordinate the investigation of how the flu virus travels. For the first time ever, 41 volunteers agreed to live together, Big Brother style, in a clinical unit in Cambridgeshire for a fortnight, exposing themselves to the flu virus. The aim was to see if transmission is caused more by large droplets that fly out when you cough and sneeze, or smaller particles, which are referred to as aerosols. 

Van-Tam explains their approach, ‘fit and healthy volunteers are given an ordinary strain of flu via nasal drops (we call them Donors). When they get symptoms, other volunteers (Recipients) join them for four days under close living conditions. Some of the recipients wear face shields and sanitise their hands every 15 minutes, and some have no protection. In this way we can study who catches flu and which routes of transmission are important.’

During the four days of the virus exposure period, and subsequent ten days, the flu recipients were constantly monitored by staff, who controlled their contact with each other. They were banned from alcohol, smoking and strenuous exercise to prevent the results being affected. 


The investigation is complex, and very expensive. Apart from the intellectual challenge of designing the correct study, the logistical issues are quite immense. Just one quarantine study requires about 18 months of planning and hundreds of staff – and they have three on the go at the moment. 

Van-Tam believes that if this research model works, it can be used to study many other related questions about flu transmission in the future.  Their findings will help decide the levels of protection for healthcare workers in flu epidemics around the world.