Summary of National Advisory Committee on Immunization (NACI) rapid response: Additional dose of COVID-19 vaccine in immunocompromised individuals following a 1- or 2-dose primary series

Publication date: September 10, 2021

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Overview

After reviewing the evidence, NACI recommends that:

*For this recommendation, moderately to severely immunocompromised includes individuals with the following conditions:

To see the full update, please visit NACI rapid response: Additional dose of COVID-19 vaccine in immunocompromised individuals following a 1- or 2-dose primary series.

What you need to know

To see the full update, please visit NACI rapid response: Additional dose of COVID-19 vaccine in immunocompromised individuals following a 1- or 2-dose primary series.

Quotes

“NACI has carefully reviewed the available data, including an assessment of benefits and harms of an additional dose, and have recommended that moderately or severely immunocompromised individuals who may have somewhat lower responses to their first vaccinations should receive a three-dose primary vaccine series using mRNA COVID-19 vaccine for the additional dose. This is not unusual for immunocompromised groups, where we often recommend different vaccine schedules to help them achieve better protection.  This is different from a booster dose, which would be used to boost an immune response that has waned over time.  NACI is also looking at whether booster doses might be needed for some key populations, but it is too early to comment on the state of the evidence for general boosters at this time.”

- Dr. Shelley Deeks, NACI Chair

“Individuals who are moderately or severely immunocompromised, including those receiving immunosuppressive therapies, are more likely to have a lower immune response to only two doses of COVID-19 vaccines. An additional dose of vaccine will increase the immune response to the COVID-19 vaccines which is expected to result in better protection. However, even with a third dose of vaccine, protection from SARS-CoV-2 infection may be lower for people with problems with their immune system. Therefore, in addition to receiving an additional dose of a COVID-19 vaccine, immunosuppressed individuals should continue to follow public health precautions such as wearing a mask. Their family and other close contacts should also be sure to receive their COVID-19 vaccine so they don’t spread infection to the immunosuppressed person.”

- Dr. Theresa Tam, Chief Public Health Officer

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