Photo: The Canadian Press

This Dec. 2, 2020 photo provided by Johnson & Johnson shows vials of its Janssen subsidiary's COVID-19 vaccine in the United States. Health Canada is just "days away" from approving Johnson & Johnson's COVID-19 vaccine, adding a fourth option to Canada's efforts to slow the spread of COVID-19. THE CANADIAN PRESS/AP-Johnson & Johnson via AP

Health Canada is just "days away" from deciding whether to approve Johnson and Johnson's COVID-19 vaccine.

If that happens it will add a fourth option to Canada's efforts to immunize our way to an end to the pandemic and the first to require only one dose.

Coupled with a new recommendation Thursday that provinces delay second doses of the other vaccines up to four months, Canada is likely to be able to offer one dose of vaccine to every adult before Canada Day.

But that dosing recommendation, and confusion about whether the Oxford-AstraZeneca vaccine is effective for seniors, have increased concerns more Canadians won't trust the vaccines enough to get in line when their turns come.

Dr. Supriya Sharma, the chief medical adviser at Health Canada, says she is concerned about vaccine hesitancy and of course would prefer it if the science around vaccines never changed.

But Sharma says that is not how science works and it would be irresponsible not to adjust the guidelines for vaccines as more data becomes available.