
The Centers for Disease Control today shared with clinicians newly revised Covid vaccination guidelines for Americans ages 12-64, those people who are moderately to severely immunocompromised and those who had the Janssen vaccine.
In issuing the changes, the CDC emphasized that the approved Covid vaccines are safe and that they already have averted an estimated 1.1 million additional virus-related deaths through November.
Out of concern over the documented but relatively tiny number of myocarditis (heart inflammation) cases that have appeared post-vaccination in younger patients, the CDC recommended a longer interval between first and second doses.

“Some studies in adolescents and adults have shown the small risk of myocarditis associated with mRNA COVID-19 vaccines might be reduced and peak antibody responses and vaccine effectiveness may be increased with an interval longer than four weeks,” the CDC report said (read it here).
More specifically, it indicated that “some people ages 12 through 64 years — and especially males ages 12 through 39 years old — may benefit from getting their second Covid-19 mRNA vaccine dose eight weeks after receiving their first dose.”
The new guidance for those Americans isn’t just about avoiding myocarditis. The same U.K. study that found rates of myocarditis/pericarditis were lower with an extended interval between the first and second doses also found that an “extended primary series interval may improve immunogenicity and vaccine effectiveness.”
For some others, the guidance said that providers should continue to recommend the three-week (for Pfizer-BioNTech) or four-week (for Moderna) intervals. Those include patients who are at higher risk of having an inadequate response to the first vaccine dose, people who are moderately or severely immunocompromised, those who are at higher risk for severe Covid, over age 65, need rapid protection (e.g. during high levels of community transmission) or are ages 5-11.
But for those who are moderately or severely immunocompromised, the CDC now recommends a three-dose primary series before they get their booster dose and a shorter period before they get their booster.

“People who are moderately or severely immunocompromised should receive a booster dose at least three months after the last (third) dose of an mRNA Covid-19 vaccine,” the guidance reads. That recommendation was previously 5-plus months.
But the changes also allow for doctors to use their own best judgment.
“On a case-by-case basis, providers who care for moderately or severely immunocompromised patients may administer mRNA Covid-19 vaccines outside of the FDA and CDC dosing intervals based on clinical judgment when the benefits of a different vaccination schedule or dosage are deemed to outweigh the potential and unknown risks.”

Finally, for those who get the one-shot Janssen Covid-19 vaccine, the CDC now recommends recipients “receive a 2nd (additional) dose using an mRNA Covid-19 vaccine at least 28 days after the Janssen dose, followed by a booster dose 2 months after the mRNA dose.” The mRNA doses include those from Pfizer and Moderna.
The CDC is also expected to revise its masking and other guidelines in the next few days.
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