Scientists Respond to CDC COVID Vaccine Guidelines: 'Asking for Trouble'

New U.S. health advice that loosens restrictions for people who are fully vaccinated is a risky move that may be "asking for trouble," according to scientists.

The Centers for Disease Control and Prevention (CDC) released guidance on Monday, saying people who have all necessary vaccine doses can visit other fully vaccinated people indoors without needing to wear a face-covering or physically distance.

Under the new rules, fully vaccinated people can now meet with unvaccinated people from one other household without needing a mask indoors—as long as those people are considered to be at low risk of severe illness from COVID.

In addition, the CDC said that fully vaccinated people are not required to distance from others or get tested unless they have symptoms after a potential exposure. Masks still need to be worn in public, and larger gatherings should be avoided.

People are considered fully vaccinated two weeks after the second dose of the Pfizer or Moderna vaccines. For the Johnson & Johnson Janssen vaccine, the recipients are considered to be fully vaccinated from COVID two weeks after a single dose.

The CDC warns on its website: "If it has been less than two weeks since your shot, or if you still need to get your second dose, you are NOT fully protected."

While scientists conceded the new guidance will be viewed by some as a welcome step towards normalcy, the consensus was clear: there are still risks involved.

Lawrence Young, professor of molecular oncology at the Warwick Medical School in Coventry, U.K., raised concerns about new COVID variants in the U.S.

He said: "Allowing fully vaccinated people to meet with those who are not vaccinated is asking for trouble—even if the unvaccinated folk are not at high risk.

"It just creates more opportunities for the virus to spread and for people to be generally less vigilant at a time when there are concerns about the spread of virus variant in New York (B.1.526), which might be more resistant to the current vaccines.

"Easing restriction measures too soon is risky when infection rates are still high and uncertainty remains about the impact of virus variants."

Broadly, the need for caution when loosening the rules was echoed by Matt Keeling, professor of populations and disease at the U.K.'s University of Warwick.

He said: "The CDC advice will be welcome news to many, and a sign that things are starting to get back to normal. However... this new advice is not risk-free.

"We know that two weeks after two complete doses of the vaccine, people have high levels of protection but they are not completely immune.

"They will have a lower risk of catching [COVID], they will almost certainly have a lower risk of transmitting the virus if they do get infected, and if they are infected they will have a lower risk of severe illness. However, the total risk to the individual is not just about the level of protection they get from vaccination, but also the level of infection in the population—while the level of infection remains high, so does the risk."

Paul Hunter, professor in medicine at the Norwich School of Medicine, University of East Anglia, echoed the belief that the updated guidance could leave people at risk of being affected by new variants of the disease, which remain in circulation.

Prof. Hunter said: "It should have been made very clear that if anyone has symptoms compatible with COVID, they should still practice self-isolation, get tested and not visit or allow others to visit them whether or not they are vaccinated.

"The big issue however is whether this guidance will remain appropriate if one of the variants with an escape mutation starts to spread rapidly within the U.S., and there is evidence that at least in some areas this may already be happening."

According to the CDC, more than 31 million people inside the U.S. are fully vaccinated against COVID as of March 8, which represents about 9.5 percent of the population. The U.S. has recorded 28.8 million cases and more than 523,000 deaths.

The health agency has said people who are at high risk of severe COVID disease include older adults, pregnant people and anyone with pre-existing medical conditions.

Moderna Covid-19 Vaccine
R.N Natalie O'Connor loads syringes with the Moderna Covid-19 Vaccine before heading out to see patients at their homes at Hartford HealthCare at Home in Bloomfield, Connecticut on February 12, 2021. Scientists have warned new U.S. health advice that loosens restrictions for fully vaccinated people are risky. JOSEPH PREZIOSO/AFP/Getty Images