WASHINGTON, Oct 22 (Reuters) - Americans can choose a COVID-19 booster shot that is different from their original inoculation but the recommendation is to stick with the vaccine they got first if it is available, White House chief medical adviser Dr. Anthony Fauci said on Friday. "It"s generally recommended that you get the booster that is the original regimen that you got in the first place," Fauci, director of the National Institute of Allergy and Infectious Diseases, said in an interview with CNN. "But for one reason or other - and there may be different circumstances with people, availability or just different personal choices - you can, as we say, mix and match," Fauci said in an interview with CNN. The U.S. Centers for Disease Control and Prevention (CDC) on Thursday recommended the COVID-19 vaccine boosters for recipients of the Moderna Inc (MRNA.O) and Johnson & Johnson (JNJ.N) shots, and said Americans can choose a different shot from their original inoculation as a booster. Fauci"s comments contrasted with the recommendations from the CDC and Food and Drug Administration this week, which said that Americans should get boosters but did not specify which combinations would be best. The recommendations also opened the door for recipients of the one-shot J&J vaccine to get a dose of the Pfizer (PFE.N) or Moderna vaccines that have been shown to afford greater protection in a variety of studies. "You can now mix and match one with the other, but in general it just makes sense to go with what your original regimen was," Fauci said. U.S. Surgeon General Vivek Murthy echoed the suggestion. "If you got a Pfizer/Moderna and if you did well with your primary series, I think it"s quite reasonable to stick with what you got originally," he said in an interview with CNBC. Studies have shown that boosters from Pfizer, Moderna and J&J all enhance protection against the virus, he said. "The bottom line is: We have good options now, we have flexibility in terms of which vaccine you get," Murthy said. Although these vaccines have been highly effective in preventing serious illness and death, some government scientists have suggested that boosters are needed to keep immunity high, especially as the extremely contagious Delta variant can cause breakthrough infections among some who are fully vaccinated.