Officials at the U.S. Centers for Disease Control and Prevention have advised Americans that fully vaccinated people do not need to wear masks in most circumstances, but the state's epidemiologist said on Thursday that he has some concerns about this guidance.

"To be honest, I'm a little bit unhappy with how CDC has rolled out their guidance. These are big changes that are decisions that are being made in the CDC guidance at a national level," Benjamin Chan said during a weekly press briefing.

Chan explained that, typically, state officials like to hear from the CDC in terms of planned guidance changes and the rationale behind the changes in the guidance.

"The first that I heard about this, actually, was through the media, and through the press conference that they had," Chan said.

Chan said although the direction has always been toward moving away from wearing masks, the difficult question has always been timing.

Chan said most states around the country, by CDC's criteria, still have a substantial level of community transmission.

"We're still in this transition phase of vaccine ramping up. There's still a large percentage of the population that is susceptible to infection and unvaccinated, and we're still at a point where there's still COVID-19 risk in our communities," Chan said.

Chan said mitigation measures and vaccinations will drive the risk of community transmission down faster and keep the numbers lower. He and other health officials will look over the guidance and see what the rationale is.

According to the CDC guidance, fully vaccinated people do not need to wear masks or physically distance in any setting, except where required by federal, state, local, tribal or territorial laws, rules and regulations.

Requirements to wear masks can come from both businesses and through workplace guidance.

Fully vaccinated people also do not have to get a test following a known COVID-19 exposure unless they are residents or employees of a correctional or detention facility. This applies to homeless shelters as well.

New Hampshire's mask mandate expired on April 16, but in some Seacoast communities, such as Durham and Portsmouth, there are still ordinances requiring people to wear masks.

Durham's ordinance expires on June 5. Portsmouth's expires on June 30.

Contact Managing News Editor Kimberley Haas at Kimberley.Haas@townsquaremedia.com or via Twitter @KimberleyHaas.

LOOK: Answers to 30 common COVID-19 vaccine questions

While much is still unknown about the coronavirus and the future, what is known is that the currently available vaccines have gone through all three trial phases and are safe and effective. It will be necessary for as many Americans as possible to be vaccinated in order to finally return to some level of pre-pandemic normalcy, and hopefully these 30 answers provided here will help readers get vaccinated as soon they are able.