The changes mean firefighters will have to self-isolate for 10 days if anyone in the same fire engine tests positive for Covid-19.
The new rules, issued by Public Health England (PHE) West Midlands, are to update what is classed as "close contact" following evidence of the new coronavirus strain's increased transmissibility.
Rod Hammerton, chief fire officer, said: "There is no doubt this change of direction will put an increased strain on the service's ability to maintain fire cover across the county, but our crews have been working tirelessly over the weekend to make sure the service is compliant with the recent directive from PHE West Midlands and all our engines are still available."
The fire service was previously advised that firefighters did not need to be treated as close contacts as they routinely wear full kit, surgical face coverings and gloves, and ensure maximum ventilation whenever within two metres of each other.
Officers were advised this weekend that due to the new variant being so much more transmissible, this was no longer the case and everyone travelling in fire engines will now need to isolate.
Mr Hammerton added: "I would like to thank all the firefighters for their swift response, ensuring that within a very few hours the new protocols were in place, making the service compliant with new guidelines.
"Structures are now established to ensure continual service delivery and disruption to operational availability has been minimised.
“Through robust planning and resilience arrangements, the service experienced minimal disruption to operational capability.”
Mr Hammerton said the service is aware that some on-call firefighters – those who are on-call or part-time and carrying out everyday jobs until an emergency call – may now be financially worse off because of the need to isolate. The fire service has pledged to ensure these people are not disadvantaged.
Staff affected will receive the same pay from the fire and rescue service as if they were working. The service will now also work with unions and primary employers to see how other impacts can be reduced.
Chairman of Shropshire Fire Authority, Councillor Eric Carter, said: “I have nothing but praise for the way Shropshire Fire & Rescue Service has handled this new information.
“There’s no margin for error in these situations and the professional response from the teams means that every measure issued has been implemented quickly and efficiently.
“Staff safety is paramount in enabling us to deliver our services and keep Shropshire safe. I have every confidence that these changes will be incorporated into operations for the benefit of our staff and the community they serve.
“I shall be lobbying government for firefighters to receive the vaccine as they form a vital element of public protection and must be able to continue their first responder responsibilities.
“Our expertise lies in responding and managing emergencies and we’d like to reassure the public and our staff that we will continue to respond to changes swiftly to ensure we can offer fire cover but also protect the staff carrying out this vital service.”
Mr Hammerton said: “Positive cases have been rising rapidly due to the new strain and have arisen through community transmission as opposed to within our workplace. Due to the rigorous safety measures we operate, our workplaces remain secure.
“We know this is due to the diligent behaviour of staff, the use of personal protective equipment worn by the crews and evidence from mass testing. It is critical that we now implement a sustainable and resilient model to support the service moving forward.”
The fire service continues to work closely with staff, unions, PHE West Midlands and five other regional fire services to ensure a consistent approach across the area.