Mixing of COVID-19 vaccines is safe, provides protection: Canada's health officials

The World Health Organization (WHO) sent ripples across the global health community during a briefing on Monday morning when a comment was made about mixing COVID-19 vaccines.

“It’s a little bit of a dangerous trend where people are in a data-free, evidence-free zone,” said WHO Chief Scientist Dr. Soumya Swaminathan. The comment was made during a portion of the briefing focused on booster shots.

Canada has yet to approve any additional shots beyond the first two, but Canadian health jurisdictions have been using the mix-and-match COVID-19 vaccine approach as of June 1, and will continue to adopt this approach as per the National Advisory Committee on Immunization’s (NACI) recommendations.

• See also:
  • Transport Canada implements rail safety measures to reduce wildfire risk
  • Unvaccinated travellers won’t be permitted into Canada for “quite a while”: Trudeau
  • Remains of one Canadian found in collapsed Miami condo

NACI updated their guidelines on second doses on June 1, 2021. They refer to the mix-and-match scenario as a “mixed vaccine schedule.”

“Emerging evidence indicates that mixed COVID–19 viral vector and mRNA vaccine schedules with dosing intervals between 4 and 12 weeks have acceptable safety profiles that may be associated with short–term increased systemic reactogenicity, which is potentially increased with shorter intervals between vaccines,” said the NACI statement.

In a statement to Daily Hive on Tuesday, Health Canada said this has been done with other vaccines.

“Vaccine interchangeability is not a new concept. Similar vaccines from different manufacturers are used when vaccine supply or public health programs change. Different vaccine products have been used to complete a vaccine series for influenza, hepatitis A, and others.“

Ontario’s Ministry of Health told Daily Hive they would also continue to follow the NACI recommendations.

“Ontario continues to follow the advice of the National Advisory Committee on Immunization (NACI) which recommends that it is safe to mix vaccines based on studies from the UK, Spain and Germany that have found that mixing vaccines is safe and produces a strong level of protection against COVID-19 and variants.”

“Mixing of mRNA vaccines (Pfizer and Moderna), as well as mixing AstraZeneca and an mRNA vaccine, is safe, effective, and enables more Ontarians to receive their second dose sooner,” they added.

BC health officials also issued a similar statement to Daily Hive, saying that the approach is working, but that they will continue to monitor the progress.

“BC’s public health is routinely gathering and monitoring data as the province’s immunization program progresses. Other countries are taking this approach as well. We are closely watching how the vaccines are working here in BC and around the world, and to date, all vaccines are proving to be highly effective in slowing the spread of COVID-19 and reducing new cases and outbreaks.”

Dr. Swaminathan later reiterated her statement on Twitter.

Individuals should not decide for themselves, public health agencies can, based on available data. Data from mix and match studies of different vaccines are awaited – immunogenicity and safety both need to be evaluated https://t.co/3pdYj4LUdz

— Soumya Swaminathan (@doctorsoumya) July 12, 2021