CDC STAFF explains Why Lengthen mRNA Vaccine Dosing Interval

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Fri, 2022-02-25 11:43 — mike kraft

Why Lengthen mRNA Vaccine Dosing Interval? CDC Staff Explain International data indicated lower risks, higher benefits for certain younger populations Molly Walker medpagetoday

Extended dosing intervals for Pfizer or Moderna vaccines may be considered for certain individuals ages 12 to 64 years, not only to lower the risk of vaccine-associated myocarditis, but to potentially improve vaccine effectiveness, CDC staff said on Thursday.

According to the agency's new interim guidance, young people ages 12 to 39 may especially benefit from a second mRNA dose 8 weeks after their first dose.

However, the regular 3-week interval for Pfizer and 4-week interval for Moderna is appropriate for patients who are moderately to severely immunocompromised, adults ages 65 and up, those who need rapid protection (such as "during high levels of community transmission"), and children ages 5 to 11.

In a call with clinicians, CDC staff reviewed the evidence to support these changes, first discussed at the CDC's Advisory Committee on Immunization Practices (ACIP) meeting earlier this month. Sara Oliver, MD, of the CDC, reviewed the mainly international data that led to the decision by showing lower rates of vaccine-associated myocarditis in men ages 18 to 24 with a dosing interval of 8 weeks or more.

Moreover, data from England showed that vaccine effectiveness for Pfizer was higher against symptomatic infection with an extended interval of more than 6 weeks versus a standard interval of 3 to 4 weeks across age groups.

"An extended interval may promote efficient T cell expansion and long-term memory cell persistence," Oliver said. ...

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