The use of face masks to protect against the spread of Covid is still being recommended in 31 US states.
The Centres for Disease Control and Prevention (CDC) are advising people wear masks in areas where the community spread is still elevated and hospital admissions are high, a decision that has been branded “outdated”.
The CDC says that when hospital admissions for Covid are low - fewer than 10 per 100,000 people – people can “choose to wear a mask at any time”.
However, when levels are medium to high - 10 to 19.9 admissions per 100,000 people - the CDC states: “If you are at high risk for getting very sick, wear a high-quality mask or respirator.”
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They said that those who live with or are in contact with someone who is high-risk should also consider wearing a mask.
Finally, when levels are high - 20 or more admissions per 100,000 people - the CDC says everyone should wear a high-quality mask or respirator and high-risk individuals should consider avoiding non-essential indoor public activities.
The majority of states fall into the “low bracket”, however some have chosen to follow the CDC's guidance or similar advice to the public health agency when outlining their recommendations.
Some of the 31 states recommending masks, which are mainly Democratic seats, include Arizona, California, Connecticut, Kansas, Maine, Montana, New Jersey, New York, Oregon, Texas, Vermont and Wisconsin.
This means that over half of the American population are being recommended to wear face mask coverings as hospitalisations increase.
However, the effectiveness of masks against Covid has been questioned by medical experts.
England’s former deputy chief medical officer said last month that there was no concrete proof that face coverings slowed down the infection rate of Covid.
Professor Dame Jenny Harries said that the evidence that masks reduced transmission is “uncertain”, due to the difficulty of designing a study to accurately test their effectiveness in real-world conditions.
She also told the UK's Covid inquiry that Government advice on how to make a mask using two pieces of cloth was “ineffective”.
Earlier this year, a systematic review of health care and policy research known as the Cochrane review, also failed to find evidence that linked mass use to reductions in Covid cases.
Dame Jenny Harries said that the evidence that masks reduced transmission is 'uncertain'
Researchers from the Cochrane Institute concluded that “wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks.”
Tom Jefferson, an epidemiologist who was the lead author of the Cochrane mask review, said: “There is just no evidence that they — masks — make any difference.”
He said to journalist Dr Maryanna Demasi that even the tougher marks “make no difference” and that researchers who advocated for mask mandates were “flawed observational studies”.
Dr Monica Gandhi, an infectious disease expert at the University of California San Francisco, told The Mail that the CDC has been too “slow” to catch up with the science.
She initially supported mask-wearing when the pandemic began, however said there is now “too much evidence” supporting not using masks over implementing widespread mask use.
Ghandi said the CDC needs to “reevaluate its outdated guidelines” by removing mask mandates.