The Ontario government will allow those who received an initial dose of Oxford-AstraZeneca’s COVID-19 vaccine to get a follow-up shot four weeks sooner than planned, bowing to mounting pressure from residents and experts alike.
Ontarians who received a shot of AstraZeneca will now be able to get their second dose — either of the same product or another brand’s mRNA vaccine — after eight weeks, rather than the 12-week wait time the province had previously required.
“This decision is based on emerging clinical evidence about the administration of two doses of different vaccines, as supported by the National Advisory Committee on Immunization (NACI),” the province said in a statement issued Saturday.
“Evidence from multiple studies indicates that mixing of COVID-19 vaccines (receiving an mRNA vaccine after an AstraZeneca vaccine) at dosing intervals between eight and 12 weeks is safe and demonstrates a beneficial immune response.”
The province had previously shortened the interval between other vaccines, frustrating those who opted to take the AstraZeneca shot.
More than 3,400 people signed an online petition urging the province to fall in line with other provinces and shorten the interval to eight weeks.
And on Friday, mayors in one long-standing COVID-19 hot spot region said residents should be allowed to speed up their immunization process and bolster their protection against more infectious virus variants.
“Residents should have the choice to be fully immunized sooner so they have better protection,” Brampton Mayor Patrick Brown wrote.
His community is part of Peel Region, where the highly contagious Delta variant has been spreading.
Evidence shows people with just one vaccine dose are less protected against the Delta variant than against other strains of COVID-19.
Members of the Ontario COVID-19 Science Advisory Table have said the key to controlling the variant is to get people fully vaccinated as quickly as possible.
The province said AstraZeneca recipients will be eligible to book their second shots as of Monday at 8 a.m., noting those who want a second dose of the same vaccine must revisit the place where they received the first one. Residents who wish to switch to the Pfizer-BioNTech or Moderna vaccines as a second shot may book through the provincial portal.
The province noted, however, that some evidence suggest waiting for a longer interval between AstraZeneca doses “provides higher protection.”
Ontario stopped administering first doses of AstraZeneca in May over what it said was an increased risk of a rare but serious blood clotting condition. It had given out nearly a million doses of the vaccine by that point.
Ontario entered the first stage of its economic reopening on Friday, clearing the way for restaurants to resume limited patio service, fitness classes to operate outdoors and non-essential retailers to re-open their doors to limited customer traffic.