Longer dose interval between vaccinations produces stronger immune response

Delaying the second dose of mRNA COVID-19 vaccination brings about a stronger immune response, claim investigators of study conducted under the Canadian COVID-19 Immunity Task Force (CITF). The peer-reviewed study looked into how the pandemic has affected paramedics in North America, and is part of a larger COVID-19 Occupational Risks, Seroprevalence and Immunity among Paramedics (CORSIP) project. The findings could inform ongoing global vaccination efforts, where half the world’s population have yet to be vaccinated.

The CITF study compared blood test results from a total of 186 paramedics, some of whom were vaccinated within the earlier recommended interval of less than four weeks, and others who received their second doses after six to seven weeks.

“We found significantly higher levels of antibodies in individuals who had longer vaccine intervals, and this was consistent regardless of which mRNA vaccine was administered,” said Dr. Brian Grunau, Assistant Professor, Department of Emergency Medicine and Scientist at the Centre for Health Evaluation and Outcome Sciences, University of British Columbia (UBC).

Widening the recommended vaccine dosing interval could facilitate faster community-level access to the first vaccine dose as well, added Dr. Grunau.

“These results support the decisions across many jurisdictions in Canada for first doses fast with an extended dosing interval,” said Dr. Tim Evans, CITF Executive Director. “The results are also very important in informing the roll out of vaccines in other countries where extending the dose interval may help to promote vaccine equity.”

Category: Features, Pharmaceuticals