Race leader Aleksandr Vlasov of Russia and Britain’s Olympic mountain bike champion Tom Pidcock were among 29 riders that were forced to pull out of the UCI World Tour event in Switzerland last Friday (June 24) after testing positive for COVID-19 with teams Alpecin-Fenix, Bahrain Victorious and UAE Team Emirates all withdrawing.

The UCI admitted there was a need to "reinforce medical surveillance of the peloton, team personnel and officials in the face of a changing epidemiological situation characterised by an increase in the number of positive COVID-19 cases recently reported".

A series of new measures have now been added to the UCI's COVID-19 policy that was last updated in January this year.

Under the revised rules, riders and staff will be required to present "at least one negative antigen test" two days prior to the start of the race.

Antigen tests will also need to be taken by other team members, UCI commissaires, UCI technical delegates and anti-doping control personnel on rest day of the event, except for days when travelling.

Should a member of the team return a positive result, they will be asked to undergo a polymerase chain reaction (PCR) test but the UCI said the decision to isolate them shall be taken by medical officials.

Among the measures deemed "strongly recommended" by the UCI include daily antigen tests for all riders and staff during the five days before the race to ensure nobody is carrying COVID-19.

Other team members, UCI commissaires, UCI technical delegates and anti-doping control personnel are also being asked to undergo testing "if possible daily but at least every two to three days" during the event.

The UCI has decided to strap the rule that authorised organisers to withdraw any team that had two or more riders returning positive PCR tests within seven days.

The COVID-19 protocol has been drawn up by a steering group led by UCI medical director Xavier Bigard in collaboration representatives of riders, teams, team doctors and organisers and has been updated several times since it was first introduced in 2020.

The latest changes come with Danish capital Copenhagen set to hold the Grand Départ of the Tour de France on Friday (July 1).

"In view of the evolution of the international health situation and on the eve of the Tour de France, it has become necessary to reinforce the measures in force to ensure that the cycling events on our international calendar can be held successfully and to protect the health of those present at the races," said UCI President David Lappartient.

"Even if the situation we are currently experiencing with the pandemic is less worrying than the one we saw at the height of the health crisis, we must remain vigilant.

"With this in mind, I call on all parties concerned to continue to scrupulously respect all the provisions of our health protocols.

"This discipline and solidarity have enabled us to maintain our activities over the past two years and will enable us to cope should the pandemic worsen in the future."