Like the rest of the world, CERN is going through challenging times due to the COVID-19 pandemic. Unfortunately, the virus did not vanish during the summer but is still circulating among the global population. In numerous countries, the number of infections is rising again – resulting in renewed constraints on our professional and private lives.

Since the beginning of CERN’s gradual restart on 18 May, the Organization has slowly been coming back to life, with more and more colleagues on site each week. And we are all excited to come back and see our colleagues in person, thus restoring the vibrant atmosphere that is so characteristic of CERN.

However, the circumstances are undeniably different and our contacts with colleagues should be reestablished with due consideration for the good health and safety of our community. The updated measures in place will help you understand how to protect yourself and others.

The following three simple gestures are easy to adopt and could save you and your colleagues from COVID-19 infection: wash your hands, keep a two-metre distance and wear face masks (correctly!). Respecting these rules will keep you and others safe; it will show you care and are taking responsibility for your colleagues’ health and well-being as much as for your own.

COVID-19 infections are mainly caused through direct or indirect contact with the SARS-CoV-2 virus when it is attached to droplets or to aerosols suspended in the air. There are three main lines of defence: keeping a safe distance of two to three metres, wearing a protective cover like a mask over your mouth and nose to reduce the spread of droplets, and the frequent renewal of ambient air with fresh air to reduce potential airborne viral concentration.

People often simply dislike wearing masks or call their efficiency into question. But there is now confirmed evidence that wearing a mask is one of the most effective ways of protecting against the spread of COVID-19. It has been shown that systematic wearing of face coverings by the community can prevent transmission of the virus, even when a wearer infected with the virus comes into close contact with others. It is therefore important that we can count on the cooperation of the entire CERN community to endorse mask wearing.

Infectious droplets can be released during breathing and speaking, even by asymptomatic infected persons. Not wearing a mask or not doing so in the correct way increases the risk of exposure to the virus for the persons in your vicinity. The wearing of a face mask is a critical barrier against the spread of the infection. At CERN, the general rule is to wear a mask at all times, except in specific settings, i.e. where a two-metre distance from others and proper ventilation can be ensured, whether indoors or outdoors (e.g. in offices or meeting rooms while seated).

Another important measure currently in place is the ventilation of office spaces to reduce the chance of infections by the virus when it is attached to aerosols. Studies show that the virus remains active for at least three hours in the air in common indoor conditions and can travel long distances. Emerging scientific evidence shows that traces of SARS-CoV-2 can be found in aerosols and small droplets even in non-healthcare settings (e.g. public spaces). Therefore proper air ventilation with fresh air should be ensured in office spaces. This may be achieved by natural means, e.g. opening windows and doors for 10 minutes at least every two hours, or by mechanical means via an HVAC system. In offices and meeting rooms where physical distancing and proper ventilation with fresh air are ensured, people may remove their masks while seated.

Our highest priority continues to be to protect the health and well-being of all people on site and those working remotely. Thanks to the measures and recommendations in place, CERN has maintained quite a low infection rate and has successfully managed the situation among the community so far. However, as we return on site, we are now all responsible for protecting the Laboratory and its future and we are all counting on each other to do the right thing.

With the COVID-19 restart plan progressing steadily and more of us returning to CERN, we expect to see the Laboratory becoming increasingly busy, but the circumstances are still unusual and we should avoid becoming complacent. This is why everybody needs to stay informed and respect the measures and recommendations in place – it is the key to a safe return for us all.