The Scottish Healthcare Workers Coalition (SHWC) has written to ministers, claiming “very serious flaws” in changing the guidance.
The group is made up of medical professionals who worked throughout the pandemic.
All members have long Covid or another chronic post-viral illness.
Face mask guidance was withdrawn in May in hospitals, dentists and GP surgeries having been in place since June 2020.
The decision came after the World Health Organization declared Covid-19 was no longer a global emergency.
The Scottish government said the country had entered “a calmer phase” of the pandemic.
Doctors from the British Medical Association (BMA) Scotland condemned the decision at the time.
The SHWC said healthcare workers were at significantly higher risk of contracting the virus and some have developed post-Covid chronic illnesses.
They warned that the decision to not enforce masks in care homes and hospitals was “playing Russian roulette” with staff and patients’ welfare.
The group is demanding the reintroduction of masks in all health and social care settings and a commitment to improving ventilation and air filtration as a matter of urgency.
Data from Public Health Scotland shows that an average of 35 Covid cases were reported daily in the week ending 9 July.
In the same week, a total of 55 people were admitted to hospital within 14 days of returning a positive test.
“Dangerous decision”
In the letter, the coalition states the updated guidance is not based on the science of coronavirus transmission and “represents a flawed and dangerous decision which will result in more infection in health and social care settings”.
Dr Shaun Peter Qureshi, of the Scottish Healthcare Workers Coalition, said: “At-risk patients have entirely legitimate concerns that they may endanger their health by visiting their GP or hospital.
“With at least 4% of NHS staff now living with chronic post-Covid complications, the Scottish government must follow the evidence and improve protections from the airborne spread (of the virus) in healthcare settings, not reduce them.”
David Osborn, a chartered safety and health practitioner, said: “It is unclear that any health and safety risk assessment was undertaken by the Scottish government before making their decision to abandon universal masking which is viewed by some patients as playing Russian roulette with their health.”
A Scottish government spokesman said: “The guidance on the extended use of face masks and face coverings in health and social care settings was withdrawn in May.
“This means that patients, service users, staff and visitors are no longer strongly recommended to wear face masks or coverings in these settings.
“This is a proportionate approach which recognises that Scotland continues to adapt to the Covid-19 pandemic and has entered a calmer phase of the pandemic.”
The spokesman said any change to the extended use of face masks and face coverings guidance was in relation to the latest scientific evidence and was continually under review.
He added: “The removal of this extended guidance does not stop or prevent staff, service users or visitors from wearing a mask.”
