A volunteer is injected with a vaccine as he participates in a coronavirus disease (COVID-19) vaccination study at the Research Centers of America, in Hollywood, Florida, September 24, 2020.Marco Bello | ReutersPublic health officials and drugmakers must be transparent about the side effects people may experience after getting their first shot of a coronavirus vaccine, doctors urged during a meeting Monday with CDC advisors as states prepare to distribute doses as early as next month.Dr. Sandra Fryhofer of the American Medical Association noted that both Pfizer’s and Moderna’s Covid-19 vaccines require two doses at varying intervals. As a practicing physician, she said she worries whether her patients will come back for a second dose because of the potentially unpleasant side effects they may experience after the first shot.”We really need to make patients aware that this is not going to be a walk in the park,” Fryhofer said during a virtual meeting with the Advisory Committee on Immunization Practices, or ACIP, an outside group of medical experts that advise the CDC. She is also a liaison to the committee. “They are going to know they had a vaccine. They are probably not going to feel wonderful. But they’ve got to come back for that second dose.”Participants in Moderna and Pfizer’s coronavirus vaccine trials told CNBC in September that they were experiencing high fever, body aches, bad headaches, daylong exhaustion and other symptoms after receiving the shots. While the symptoms were uncomfortable, and at times intense, the participants said they often went away after a day, sometimes sooner, and that it was better than getting Covid-19.Both companies acknowledged that their vaccines could induce side effects that are similar to symptoms associated with mild Covid-19, such as muscle pain, chills and headache.One North Carolina woman in the Moderna study who is in her 50s said she didn’t experience a fever but suffered a bad migraine that left her drained for a day and unable to focus. She said she woke up the next day feeling better after taking Excedrin but added that Moderna may need to tell people to take a day off after a second dose.”If this proves to work, people are going to have to toughen up,” she said. “The first dose is no big deal. And then the second dose will definitely put you down for the day for sure. … You will need to take a day off after the second dose.”During the meeting on Monday, Patsy Stinchfield, a Children’s Minnesota nurse practitioner, said officials and drugmakers could try talking about the side effects in a more positive way. She said they could use language such as “response” instead of “adverse reaction.””These are immune responses,” said Stinchfield, a past voting member of the committee. “And so if you feel something after vaccination, you should expect to feel that. When you do, it’s normal to have some arm soreness or fatigue, some body aches and maybe even a fever. It sounds like in some of these trials, maybe even having to stay home from work.””You hear some people in the trials that are disappointed that they didn’t have any of those things, feeling they must have gotten a placebo,” she added.The committee meeting comes three days after Pfizer and its partner BioNTech applied for an emergency use authorization from the Food and Drug Administration for their coronavirus vaccine.The FDA process is expected to take a few weeks, and an advisory committee meeting to review the vaccine has been scheduled for early December. Some Americans could get their first dose of the vaccine in about a month.ACIP is expected to call an emergency meeting to make specific recommendations on distribution once the FDA authorizes a vaccine.Federal agencies are already sending vaccination plans around to staff. Five agencies have started telling employees they could receive Pfizer’s or Moderna’s Covid-19 vaccine in as little as eight weeks, a person with firsthand knowledge of those plans told CNBC on Friday.