Pathfinder
Editor, Senior Moderator
Summary and Work Group Interpretation:
Extended intervals for
mRNA COVID-19 vaccines
Sara Oliver, MD, MSPH
ACIP Meeting
February 4, 2022
...
VaST assessment – Myocarditis/pericarditis following
Moderna and Pfizer-BioNTech COVID-19 vaccination
VaST reviewed the most recent data from three U.S. safety monitoring systems*
, and well as data from international partners
Reported rates of myocarditis/pericarditis following mRNA COVID-19 vaccination
are higher than background; rates are highest after dose 2 in adolescent and
young adult males
In most safety monitoring systems, myocarditis/pericarditis risk appears higher
after dose 2 Moderna than dose 2 Pfizer-BioNTech COVID-19 vaccination
Data are limited on myocarditis/pericarditis risk following different dose 1-dose 2
intervals+
Summary: International data
Myocarditis after mRNA COVID-19 vaccines
Risk of myocarditis/pericarditis was higher for Moderna than Pfizer vaccine
– The highest risk was seen after the second dose among younger males
Rates of myocarditis/pericarditis were lower with extended interval
(≥8 weeks) between first and second dose of mRNA vaccine primary series
...
Considerations regarding extended intervals between
first and second doses of mRNA vaccine (primary series)
Possible Benefits
Safety:
– Extended interval appears to reduce the risk of myocarditis
– Lowest rates of myocarditis with interval at 8 weeks
Effectiveness:
– Extended interval appears to increase VE for primary series
– Benefit may ‘level out’ at ≥8 weeks
Implementation:
– Possibility that uptake for COVID-19 vaccine primary series could increase if
individuals/parents desire action to lower risk for myocarditis
Considerations regarding extended intervals between
first and second doses of mRNA vaccine (primary series)
Possible Risks
Effectiveness:
– Longer duration of time where individual only have the benefit of a single dose of
mRNA vaccine
Implementation:
– For aspects that require being ‘fully vaccinated’ (shorter quarantine, travel or
restaurants, etc), extending interval would extend the time before being ‘fully
vaccinated’
Work Group Interpretation
An individual’s risk of getting COVID-19 likely increases the longer they are only
partially vaccinated with a single dose
The risk would need to be balanced with the benefits of lowering rates of
myocarditis and optimizing the long-term vaccine effectiveness
This balance is influenced by trajectory of pandemic and recent epidemiology of
COVID-19, and can change over time
Early in the pandemic, the priority was for individuals to have optimum
protection from the primary series as quickly as possible
– Guidance around COVID-19 vaccines can be updated as new data become available
and the focus expands to the future of the COVID-19 vaccine program
Work Group Interpretation
Clear communication for COVID-19 vaccines and preferred intervals is important
May be populations where the benefits of earlier interval (3 or 4 weeks) would
outweigh possible risks of myocarditis
– Licensed intervals of 3 weeks (Pfizer-BioNTech) or 4 weeks (Moderna) continue to be
recommended, especially in circumstances where early protection is desired
The Work Group supported a preferred interval of 8 weeks between the first and
second dose of an mRNA COVID-19 vaccine primary series
...
https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2022-02-04/12-COVID-Oliver-508.pdf
https://www.cdc.gov/vaccines/acip/meetings/slides-2022-02-04.html
Extended intervals for
mRNA COVID-19 vaccines
Sara Oliver, MD, MSPH
ACIP Meeting
February 4, 2022
...
VaST assessment – Myocarditis/pericarditis following
Moderna and Pfizer-BioNTech COVID-19 vaccination
VaST reviewed the most recent data from three U.S. safety monitoring systems*
, and well as data from international partners
Reported rates of myocarditis/pericarditis following mRNA COVID-19 vaccination
are higher than background; rates are highest after dose 2 in adolescent and
young adult males
In most safety monitoring systems, myocarditis/pericarditis risk appears higher
after dose 2 Moderna than dose 2 Pfizer-BioNTech COVID-19 vaccination
Data are limited on myocarditis/pericarditis risk following different dose 1-dose 2
intervals+
Summary: International data
Myocarditis after mRNA COVID-19 vaccines
Risk of myocarditis/pericarditis was higher for Moderna than Pfizer vaccine
– The highest risk was seen after the second dose among younger males
Rates of myocarditis/pericarditis were lower with extended interval
(≥8 weeks) between first and second dose of mRNA vaccine primary series
...
Considerations regarding extended intervals between
first and second doses of mRNA vaccine (primary series)
Possible Benefits
Safety:
– Extended interval appears to reduce the risk of myocarditis
– Lowest rates of myocarditis with interval at 8 weeks
Effectiveness:
– Extended interval appears to increase VE for primary series
– Benefit may ‘level out’ at ≥8 weeks
Implementation:
– Possibility that uptake for COVID-19 vaccine primary series could increase if
individuals/parents desire action to lower risk for myocarditis
Considerations regarding extended intervals between
first and second doses of mRNA vaccine (primary series)
Possible Risks
Effectiveness:
– Longer duration of time where individual only have the benefit of a single dose of
mRNA vaccine
Implementation:
– For aspects that require being ‘fully vaccinated’ (shorter quarantine, travel or
restaurants, etc), extending interval would extend the time before being ‘fully
vaccinated’
Work Group Interpretation
An individual’s risk of getting COVID-19 likely increases the longer they are only
partially vaccinated with a single dose
The risk would need to be balanced with the benefits of lowering rates of
myocarditis and optimizing the long-term vaccine effectiveness
This balance is influenced by trajectory of pandemic and recent epidemiology of
COVID-19, and can change over time
Early in the pandemic, the priority was for individuals to have optimum
protection from the primary series as quickly as possible
– Guidance around COVID-19 vaccines can be updated as new data become available
and the focus expands to the future of the COVID-19 vaccine program
Work Group Interpretation
Clear communication for COVID-19 vaccines and preferred intervals is important
May be populations where the benefits of earlier interval (3 or 4 weeks) would
outweigh possible risks of myocarditis
– Licensed intervals of 3 weeks (Pfizer-BioNTech) or 4 weeks (Moderna) continue to be
recommended, especially in circumstances where early protection is desired
The Work Group supported a preferred interval of 8 weeks between the first and
second dose of an mRNA COVID-19 vaccine primary series
...
https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2022-02-04/12-COVID-Oliver-508.pdf
https://www.cdc.gov/vaccines/acip/meetings/slides-2022-02-04.html