Ask the Doctor Question:
My husband has just started SCIG for secondary immune deficiency. How soon would any of the globulin he is receiving start to offer some protection against COVID? (We are in Canada.)
Answer: SCIG in Canada is similar to what we refer to as IVIG in here in the US. Unfortunately, it does not provide a reliable level of protection against COVID-19.
It works very similar to convalescent plasma. However, you may have noticed that there isn’t much mention anymore of using convalescent plasma as a form of treatment against COVID, especially since the variants emerged. And convalescent plasma has never been used as a preventative (prophylactically), only for treatment AFTER infection.
Using IVIG for prevention of COVID-19 has been tested but is completely unproven. The main reason IVIG doesn’t reliably provide protection against COVID-19 is because it is manufactured from thousands of other pooled blood donors. So, there is such a high level of variation in the number of COVID-19 antibodies that may or may not be present from batch to batch. And you never know how many antibodies you are going to get. This makes its effectiveness very unpredictable. There are a few very weak studies which indicate IVIG might keep COVID-19 disease from progressing to severe should you ever test positive, but monoclonal antibodies after infection now do a much better job.
That being said, there really is not a downside to receiving it, except for the increased risk of blood clots. Just know that while receiving IVIG wouldn’t hurt, the chance of gaining any immunity from it is extremely unlikely and unpredictable.
The best thing you can do right now is to continue taking all precautions just as if you were never vaccinated, limit interactions, and (if possible) wear a tightly fitted N-95 mask while around other people.
Additionally, please make sure you have completed your COVID-19 planning checklists ahead of time. Knowing where you can access anti-SARS-CoV-2 antibodies is of the utmost importance. If you haven’t accessed these checklists already, please visit our website’s CLL Society COVID-19 Plan section found here: https://cllsociety.org/2021/07/covid-19-plan-checklists-for-chronic-lymphocytic-leukemia-cll-preparing-for-pre-and-post-covid-19-exposure/