(Island Health)

Health Canada announced on Friday that they have approved Johnson & Johnson’s COVID-19 vaccine.

The Johnson & Johnson vaccine marks the fourth vaccine Health Canada has approved and is also the first single-dose vaccine approved in the country.

Compared to the other vaccines, the Johnson & Johnson has a lower efficacy but can be stored at refrigerated temperatures of 2 and 8 degrees celsius for 3 months.

The Pfizer and Moderna vaccines store at -70 and -20 degrees, and have an efficacy of 95 per cent and 94.1 per cent, respectively.

The approval of the Johnson & Johnson comes a week after the approval of the AstraZeneca vaccine.

Like AstraZeneca, the Johnson & Johnson vaccine is a vector-based vaccine.

Vector technology has been used by scientists since 1970 and is used with gene therapy and cancer.

The Johnson & Johnson vaccine has only been approved for adults 18 and older, as of now.

A clinical trial of for the ages between 12 and 17 has been authorized by Health Canada.

Side effects can include pain and tenderness near the injection site, headache, muscle pain, and a mild fever and chills – all which resolve in a few days.

“The benefits outweigh the potential risks,” Dr. Supriya Sharma, Health Canada’s chief medical adviser,

She also reiterated that regardless of efficacy, all of the vaccines are good in fighting against areas that matter most – preventing serious illness, reducing hospitalizations, and curbing the number of deaths.

Canada has ordered 10 million doses from Johnson & Johnson, with options for up to 28 million more.

Canada is expected to see the first doses near the beginning of April.

What is a viral vector based vaccine?

All of the vaccines aim to produce immunity to the SARS-CoV-2 virus by stimulating an immune response to an antigen 3 – a foreign substance which induces an immune response in the body, especially the production of antibodies.

Typical vaccines introduce a modified or weakened version of the virus/antigen, so that your antibodies can build an immune response and stave off the virus.

Whereas, the mRNA vaccines (Pfizer and Moderna) and the viral-vector vaccines (AstraZeneca and Johnson & Johnson) work by using the cells in a patient’s body to produce the antigens themselves.

These vaccines create antigens which trigger an immune response, and viral vector vaccines insert their genetic into a harmless virus (adenovirus) without causing disease into the subject.

This triggers a strong immune response without the need for an adjuvant – a booster.

This is why the Johnson & Johnson vaccine is administered in one dose.

In theory, one type of vector can be used to deliver code for a range of different antigens, which can speed up vaccine development.

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