Dr. Jonathan Edelman, On Clinical Data Supporting the Efficacy of Influenza Vaccine in Young Children

Seqirus, a global leader in influenza prevention, recently presented Phase III clinical data demonstrating that the company’s cell-based quadrivalent seasonal influenza vaccine (QIVc) was as safe and immunogenic as a standard quadrivalent seasonal influenza vaccine (QIV) in children six months through <4 years of age during the U.S. 2019/20 influenza season.

DocWire News spoke with Dr. Jonathan Edelman, Vice President, Clinical Development at Seqirus, to discuss these data.

DocWire News: Can you talk to us about this influenza vaccine?

Dr. Jonathan Edelman: Sure, I’d love to. QIVc, or Flucelvax Quadrivalent, is a vaccine that is available in the U.S. It’s the first and only influenza vaccine that is based on a cell technology, and I can explain a little bit about that if you’re interested.

The important point about Flucelvax is that the vaccine itself is as closely matched to the circulating viruses that the vaccine is intended to protect against. And the reason for that is that these viruses are grown in cells in the culture dish, in the factory, just the same way as when you’re infected with the virus, they grow inside your body in your cells. And what comes out is a vaccine that protects you as closely as it can against the virus that’s circulating.

That’s different from the egg-based vaccines that are out there, because in order for a human influenza virus to grow in eggs, it needs to adapt sometimes. They’re not naturally like to grow in eggs. And the consequence is that the match, certain times, certain seasons, certain viruses, the match between the virus that you’re trying to protect against and the one that goes into the vaccine is not that good.

DocWire News: Can you describe the study that assessed the efficacy of this vaccine?

Dr. Jonathan Edelman: This study was one of a series of studies that we’ve been conducting to establish the immunogenicity, the way in which the Flucelvax vaccine offers its protection against seasonal influenza across the age spectrum. The vaccine has been studied in subjects now as young as six months of age, and this particular study focused on children from six months to four years of age.

The reason we start at six months is that there’s good evidence that younger children below that are protected from the nursing mother’s milk. But beyond that, the immunity wears off, and these children, particularly the youngest, are vulnerable to serious complications if they get influenza.

We had already established that Flucelvax was an effective vaccine for children down as young as two years of age, and this study expands that down to six months of age. And the way we did it is we compared this vaccine, Flucelvax, in six months to four-year-old children with a standard vaccine, and we determined that it is both safe and equally effective in raising an immune response. And this is an important finding because it firmly establishes that Flucelvax will be an effective vaccine in children down to six months of age. We’re in the process of having the data from this study reviewed by the FDA, and we are hoping for a positive outcome and an expanded indication fairly soon.

DocWire News: Is the severity of influenza compounded amid the COVID-19 pandemic?

Dr. Jonathan Edelman: You know, it’s a really interesting observation about COVID and influenza. There was quite a bit of concern early on in the COVID pandemic of what was called the twindemic; the possibility of people having both influenza and COVID. There was a very strong drive to encourage vaccination for people of all ages in the United States, and what we observed was record vaccination rates for influenza in this country.

And we also observed a very light influenza season. There were sporadic cases of people who were infected with both diseases, but it turned out that influenza was relatively quiet. And largely, I think, that has to do with the fact that COVID was such a virulent and easily spread disease. But make no mistake, influenza is not gone. And as the COVID pandemic recedes, as vaccinations go more broadly in the United States against COVID, influenza will make a resurgence.

And because the population has not really been exposed in this past year to influenza very much, when influenza viruses do recur, they will be a variation of that virus, because it’s constantly changing, that the human population has not seen or not seen as recently or as well. And the likelihood of that resulting in a bad influenza season is much higher, so the importance of getting vaccinated against influenza remains just as high as it was during COVID as it will be as COVID begins to recede.

Just to give you an example, in the year we did the study that you’re talking about, there were over 2,000 children enrolled in our study. In that year alone, 52,000 children were hospitalized for influenza and over 400 died. People don’t realize how significant influenza disease can be, and one of the best things that you can do to prevent that is to get vaccinated. That is probably the single most important element of public health advancement for influenza that anyone can do. And that’s one of the reasons why we’ve taken the effort to expand the indication for our vaccine down to the youngest, most vulnerable kids.

DocWire News: Closing thoughts?

Dr. Jonathan Edelman: I think it’s really important to remember the guidance that comes from the CDC about the importance of being vaccinated. It’s essential that this be an ongoing effort. In the United States, the recommendation is that anyone six months of age or older get vaccinated. And I think having a vaccine like Flucelvax that as closely matches the targeted circulating viruses as possible is an important element in the armamentarium to benefit the public health. I hope that’s helpful information for people.