Amid B.C.’s plan for COVID boosters, new research suggests those doses may not be necessary yet

People with two doses of AstraZeneca have shown waning levels of protection from infection, but are still well protected from severe illness, Dr. Bonnie Henry said Monday.

Anyone in British Columbia who received two doses of AstraZeneca’s COVID-19 vaccine can now get a booster six months after their second shot, B.C.’s top doctor said Monday.

People with two doses of AstraZeneca have shown waning levels of protection from infection, although two doses of AstraZeneca still offer strong protection against severe illness, Dr. Bonnie Henry said Monday.

“This may be sooner than other healthy adults in the community where we know there’s very good, strong protection that’s lasting well,” Henry said.

Several new studies indicate that a booster may not yet be necessary for those who received either two doses of mRNA or a mix of AstraZeneca and mRNA vaccines, if those doses were administered at an interval of eight to 12 weeks.

Brian Grunau with the University of British Columbia’s Dept. of Emergency Medicine said early results from a study of paramedics across Canada show that longer vaccine dosing intervals lead to enhanced immune responses.

“The interaction between vaccine dosing intervals may play a role in the timing and need for third vaccines,” he said.

“Our data suggest that the immune response is prolonged in those who have longer vaccine dosing intervals, so this may make individuals who have longer dosing intervals less required of a booster shot earlier on.”

Some other researchers aren’t convinced that booster shots are needed for everyone yet. Dr. Danuta Skowronski at the B.C. Centre for Disease Control previously told Global News the immune response from two shots administered at proper intervals is so robust that most healthy adults don’t need a booster yet.