The National Advisory Committee on Immunization quietly updated its recommendations on Tuesday to indicate that the second dose of the COVID-19 vaccine can be given up to six weeks after the first dose.
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According to pharmaceutical prescriptions, the booster dose should be injected three weeks after the first in the case of Pfizer / BioNTech vaccine or four weeks after that of Moderna, in order to ensure optimal long-term immunization against the disease.
However, the Committee believes that, while it is preferable to follow these instructions, the provinces can afford to delay the administration of the second dose, depending on “the logistics of vaccine delivery, the current epidemiological situation and projections, as well as the capacity of the health system ”.
“Some provinces and territories can maximize the number of people receiving a first dose of vaccine by delaying the administration of the second dose until other vaccine supplies are available, preferably no more than 42 days. after the administration of the first dose, ”continued the committee.
More generally, the committee called on the provinces to find a “balance” between vaccinating as many people as possible and administering the second dose.
“Principles of immunology, vaccine science and historical examples demonstrate that delays between doses do not cause reduction in final antibody concentrations, nor decrease in the durability of the anamnestic response for most products. administered in multiple doses, ”the committee stressed in support of its position, while acknowledging that clinical trials of COVID-19 vaccines have been short-lived.
This notice brings water to the mill of several provinces, including Quebec, which have chosen to opt to delay the administration of the booster dose. La Belle Province is currently awaiting the opinion of its own expert committee to find out how far it can afford to stretch the elastic.
This strategy has however detractors, such as the Committee for the Defense of Families of the Maimonides Geriatric Center. This grouping demanded again, Tuesday, that Quebec administers the second dose within the time limits set by the pharmaceutical companies, in the wake of the announcement of seven infections affecting patients of the Maimonides center already vaccinated for the first time.
According to data from clinical trials, the first dose of vaccine can reduce the chances of contracting COVID-19 by about 90%, two weeks after its inoculation.