Thank you, Dr. Tam.
Thank you, Chair, for the question and the opportunity to respond.
It's an excellent question. Part of the challenge we see here is that we have an expert advisory committee like NACI, which provides expert and evidence-based advice to provinces and territories and to the Public Health Agency of Canada, which then turn it into communication materials. What we see is a very motivated and interested media and public who like to look straight to the source to see what the advice is from the advisory committee. There's some complexity, I think, in the communication pathways there.
Something we've seen throughout the pandemic and throughout the vaccine program is that NACI has consistently given advice in real time as evidence continues to evolve. What the member may be referring to is when the bivalent vaccines were first introduced to the booster program. As Dr. Tam mentioned, NACI recommended that the bivalent vaccine could be used as a booster option and that boosters were important, particularly for the elderly and with the six-month interval, as Dr. Tam outlined. As the product environment has evolved and as the evidence has strengthened about the bivalent boosters, NACI recently recommended that bivalent vaccines are now, in fact, preferred for those in the authorized age groups, where they're available.
Again, this demonstrates an evolution of the science. The expert advice moves along as the science strengthens and evolves, and then the committee adjusts the strength of its recommendations. It is now clear that there are two good options for this bivalent product, and the committee was of the opinion that this would be preferred now. That is a strong recommendation for the bivalent product as being preferred, whereas earlier in the program it was being onboarded as one of the many important booster options.
I think this is something we'll continue to see occurring. As expert advice is evolving in real time—and we know that COVID-19 evidence and vaccine science are evolving as quickly as possible—we're all very closely reading every preprint and every publication that comes out to try to get the edge on the virus and get the edge on the best science. That's a function of the system of this medical and evidence-based advice coming through in real time as things are evolving.
As Dr. Tam mentioned, the important takeaway is that at this point, the bivalent vaccines—those boosters that are approved for several age groups—have been shown to have high levels of antibody, which we expect will result in protection against omicron and the other variants. The goal this fall of the program is to use those vaccines to try to diversify the immune response; it's not necessarily to have the closest match to exactly what is circulating today. We know that omicron variants are the most distinct from the original ancestral strain, so providing a vaccine that covers both of those allows the immune system an opportunity to establish a strong breadth of protection that we think will be important going through this winter for the program.