Good morning. My name is Livia, and welcome to Moderna's conference call. At this time, all participants are on a listen only mode. Following the formal remarks, we will open the call up for your questions. Please be advised that the call is being recorded. At this time, I would now like to turn the call over to Lavina Talukdar, Head of Investor Relations at Moderna. Please proceed.
Thank you, Olivia. Good morning, everyone, and thank you for joining us on today's call to discuss Moderna's bivalent COVID booster phase II/III interim analysis. You can access the press release issued this morning as well as the slides that we'll be reviewing by going to the investor section of our website. On today's call are Stéphane Bancel, our Chief Executive Officer, Stephen Hoge, our President, and Paul Burton, our Chief Medical Officer. Before we begin, please note that this conference call will include forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Please see slide two of the accompanying presentation in our SEC filings for important risk factors that could cause our actual performance and results to differ materially from those expressed or implied in these forward-looking statements.
I will turn the call over to Stephen, who will take us through the data. Stephen?
Thank you, Lavina. Good morning and good afternoon, everyone. Starting on slide three, I'd first like to frame our strategy for COVID boosters and why we are pursuing bivalent boosters in the seasonal update. The strategic rationale for seasonal booster at Moderna is based on three points summarized here. We see neutralizing titers will wane similar to endemic human coronaviruses which circulate every year, and that decline in neutralizing titers, we believe, will increase the risk of breakthrough hospitalization for those at higher risk, including older adults and immunocompromised. We also believe that there will be emergence of new strains of variants of concern that could accelerate the impact of that waning and broadening the risk of breakthrough. In fact, we see that happening right now with the Omicron variants of concern and sublineages. What are the desired features for an updated vaccine?
Well, the first would be to improve the durability of protection from neutralizing antibodies against Omicron to at least six months, and that would provide full protection through the fall-winter respiratory infection season that happens every year with other viruses, and we believe will happen again this year with SARS-CoV-2. Second, we wanna retain high-end durable protection against prior variants of concern and the ancestral strains. We do not wanna be opening up any gaps in the immunity that we've already achieved. Third, we hope to broaden the cross-protective immunity to increase the potential protection as the variants of concern continue to evolve mid-year. Now, in order to do that, we've been advancing a range of bivalent vaccines against different variants of concern.
On slide four, I'd like to summarize the phase II/III study, our mRNA-1273-P205 study, for our most recent bivalent vaccine with mRNA-1273.214. mRNA-1273.214 is a bivalent, including 25 mcg of our prototype vaccine, 1273, and 25 mcg of mRNA-1273.529. That is an updated antigen for the Omicron variant of concern. The bivalent vaccine here includes Omicron and helps educate the immune system about what Omicron looks like. Now in the phase II/III study, mRNA-1273-P205, all subjects in this study had previously received mRNA-1273 as a primary series, so the two doses of 100 mcg. They had all received a 1273 prototype booster of 50 mcg.
On entry to the study, people then received either a fourth dose of mRNA-1273 or a fourth dose of the bivalent booster. That includes the 32 Omicron mutations, both at 50 mcg. As you can see here, approximately 370 subjects were enrolled in a prototype arm, and approximately 430 subjects, 437, were enrolled in the bivalent vaccine arm. Now we have another study ongoing in the United Kingdom with about 1,500 participants per arm, where there are mixed primary regimens, not just mRNA-1273. The arms were enrolled sequentially, but very quickly after each other in February and March this year. Now on slide five, I'd like to quickly remind you of the primary objectives for the study. They were consistent with regulatory guidance.
The first set of endpoints we evaluated were day 29 immunogenicity, and we tested first non-inferiority against the ancestral SARS-CoV-2 strain, as well as non-inferiority in seroresponse rates. Having met those criteria, we then moved on to superiority in terms of geometric mean ratio against Omicron at day 29. I'll cover that data in just a couple of moments. First, on slide six, quickly I wanna summarize the demographics and baseline characteristics between the two groups, and they were generally very consistent. The mean age, as you can see, between the bivalent vaccine recipients, 1273.214 in the middle column, and those who received the prototype vaccine on the far right column, was 57 years old in both cases. The percentage of participants over the age of 65 was 39.8% in both cases. There was good gender balance.
In terms of the duration between doses, those who received the two vaccines had very similar. It was eight months median duration between the completion of the primary series and the first booster dose, the 50 mcg booster dose of 1273 in both groups. Between the first booster dose and the dose received in this study, it was approximately 4.5 months in mRNA-1273.214, the bivalent, and 4.4 months in the prototype. Again, very similar. Both groups also had very similar percentage of baseline seropositive participants. 22% of those in the bivalent arm had had a prior SARS-CoV-2 infection, either documented based on nucleocapsid antibody or a PCR test that was positive upon baseline testing in the study. The comparable group in the prototype arm was 26.8%.
Very similar overall in terms of characteristics. Moving on to safety very quickly. The solicited adverse reactions on slide seven were consistent with prior doses. First looking on the left at local solicited adverse reactions reported within seven days of the dose, and on the right at systemic, we've presented the complete data here across our range of doses. Quickly to orient you to this slide, the grade three are in orange, grade two in green, and grade one in blue. You've got three pairs of bars in each case. The furthest bar on the left is the solicited adverse reactions from our phase III study after a second dose of mRNA-1273. As a reminder, that was a 100 mcg second dose.
The middle of the three paired bars is the P201 phase II data from the first booster that was formed the basis of our approval of a 50 mcg booster of mRNA-1273 or Spikevax. The third of the three bars is the reported reactogenicity in the current study, the phase II/III study here for the bivalent vaccine. As you can quickly see across all of the solicited local and systemic reactogenicity parameters, generally they were broadly consistent. In fact, there was a numerical trend towards lower reactogenicity for the 214 bivalent booster, fourth dose booster, compared to either the prior booster dose or the second dose of the primary series.
In addition, the frequency and types of unsolicited adverse events were also comparable between the groups, and there were no vaccine-related serious events in the bivalent vaccine group up to 28 days after booster dose. All very reassuring and consistent with prior experience. Now moving on to slide eight are the immunogenicity results against Omicron, the variant of concern that we are principally trying to develop this improved booster for. Here I'm showing you the pseudovirus neutralization titers against Omicron for all of the different groups in a few different groups. Just to orient you to the slide quickly, on the far left are all participants in the study, those who were both seropositive and seronegative. In the middle, as denoted, there are the seronegative participants, those who were baseline seronegative to SARS-CoV-2 prior to boosting.
On the far right, those participants who were baseline seropositive, who had had a history of a SARS-CoV-2 infection. In the lighter purple color is the prototype vaccine, and in the darker purple color is the bivalent Omicron-containing vaccine. As you can quickly see, the baseline titers, pre-booster titers across all participants, seronegative and seropositive, were very similar between the groups. As I think you can quickly appreciate, the resulting boosting of day 29 titers led to higher, numerically higher, significantly higher neutralizing titers across all three subgroups. Focusing first on the seronegative population, you'll see that the total titers got to 2,400 approximately, and that compares with 1,473 for the day 29 titers of those who'd received the prototype vaccine.
Importantly, if you look at seropositives, there was also a benefit with significantly higher titers, up to 7,600 compared to 3,800 for those who are seropositive. In the all participant group, which is a blend of the two to the right and may accurately represent the population of folks who will be boosted this coming fall, we still saw a significantly higher rate of neutralizing titers despite very similar starting baseline titers and similar demographic characteristics. Moving on to the statistical testing on slide nine, the first question, as per protocol, is and as per regulatory guidance, was can we get the superior neutralizing titers against Omicron. This is now looking only at the baseline seronegative participants and the per protocol statistical analysis.
You can see here again in the middle column the bivalent booster data in terms of neutralizing titers, and then the far right column of the three, the prototype vaccine. Pre-booster titers were similar, approximately 300 in both cases. As I covered a moment ago, the ANCOVA model estimated GMTs were significantly boosted in the case of the bivalent vaccine to 2,400, and GMFR, geometric fold mean boosting, was approximately eight-fold, 7.96 in this calculation. That compares with the prototype vaccine, which did succeed in boosting titers against Omicron on a fourth dose. Again, this is a fourth dose, whereas prior results had been published with a third dose, and boosted from 300 approximately to about 1,400. That's a four-fold boost. The geometric mean ratio between those two was 1.75, so a point estimate above one.
Importantly, the lower bound of the confidence interval was as high as 1.49, so a statistically significant superior result. In terms of seroresponse rate at day 29, where we wanted to demonstrate non-inferiority, there was really no difference between the vaccines. Although numerically higher superior seroresponse rate for the bivalent vaccine, that was not statistically significant, given the strong seroresponse that we see with mRNA-1273 prototype. In summary, all primary and key secondary immunogenicity objectives were met on the study, and the bivalent vaccine did elicit superior neutralizing antibody responses against Omicron compared to prototype. It also elicited non-inferior seroresponse rate, as was the objective. mRNA- and lastly, the bivalent vaccine induced potent neutralizing antibody responses against Omicron in all seronegative respondents tested individuals.
Now quickly on slide 10, just to show that as we look at a population that might be more representative of the broader population who are gonna be boosted this fall, which is all participants, including those who are seropositive, the results are remarkably similar. While pre-booster titers are numerically higher and the post-booster titers are also numerically higher, heading to 3,000 in this case, for the bivalent vaccine, 3,232, the fold, the GMFR and geometric mean ratio are very, very similar. In fact, geometric mean ratio here was still statistically significantly superior at 1.78, with a lower bound of 1.56 compared to 1.49 in the other group. You can appreciate those are remarkably consistent.
The seroresponse rate was also numerically higher for the bivalent vaccine but not significantly so, and again, very reassuring in the context of this study. The bivalent vaccine resulted in superior neutralizing GMT, therefore, against Omicron compared to the prototype for all the participant subgroups, both seronegative and seropositive participants, as well as the combined cohort. Very reassuring for the direction of this booster. Last thing on slide 11, just to orient you to the data, is we did wanna confirm that the vaccine, the bivalent booster continued to have non-inferior protection against ancestral SARS-CoV-2 strains, in this case, the D614G bearing ancestral assay. This is the same assay in which we've consistently been testing our samples throughout our clinical trials over the last several years. On the left, you're looking at the all participants, and on the right baseline seronegative participants.
On the left, I think you can appreciate the geometric mean ratio was 1.2, highlighted in red there. The lower bound of the confidence interval excludes one, so 1.08, meaning that the bivalent booster also demonstrated superior neutralizing protection in terms of neutralizing antibodies against the ancestral SARS-CoV-2 strains, even though the only goal was non-inferiority. Again, very reassuring that the bivalent vaccine is not only significantly improving protection against Omicron as measured by neutralizing titers, but it is also retaining strong protection, in fact, providing slightly superior protection against the ancestral strains of the virus. On slide 12, briefly, just to summarize the conclusions. mRNA-1273.214.
The bivalent Omicron-containing booster, the 50 mcg booster, was well-tolerated, and the safety and reactogenicity profile was similar to what we've seen with prior doses of the prototype. All the primary and key secondary immunogenicity objectives were met. The bivalent vaccine elicited a superior neutralizing antibody response against Omicron compared to the prototype, and it elicited non-inferior neutralizing antibody responses against the ancestral SARS-CoV-2 strains, which was the objective. We also elicited strong neutralizing responses against all individuals, regardless of whether they had a prior SARS-CoV-2 infection or not, clearly indicating there was a benefit to boosting even in those who've been infected with SARS-CoV-2. Overall, we believe this very encouraging data, you know, clearly shows that the bivalent booster is a superior booster.
As we look to the fall infection season with respiratory viruses, with SARS-CoV-2 and the ongoing circulation of Omicron and its subvariants, we believe strongly that this data supports an update of the vaccine from the sequence that we've been using from years ago to the bivalent Omicron-containing booster demonstrated here. Moderna is preparing regulatory filings based on this data, and we expect to submit them in the coming weeks. We're very optimistic, given that we have met those regulatory guidance and the pre-specified criteria in this study, that we'll be able to have a vaccine available by the late summer and early fall, for protection against SARS-CoV-2 in the winter infection season. With that, I think we'll be happy to take any questions.
Ladies and gentlemen, if you'd like to ask a question at this time, you will need to press the star then the one key on your touchtone telephone. Please stand by while we compile the Q&A roster. Now first question coming from the line of Salveen Richter with Goldman Sachs. Your line is open.
Hey, guys. Good morning, and thank you for taking our questions. This is Elizabeth on for Salveen. Regulatory-wise, could you just walk us through the next steps post this candidate working, and, you know, expectations for the June 28th meeting? Then, could you also comment on how Moderna is working to get a supply of this candidate ready for the fall? Thank you.
Absolutely. Thank you for the question. We have obviously been engaged with regulators globally, including the FDA in the United States, about the criteria for this study since the early part of this year and have reviewed those protocols, you know, and designed the study to meet that guidance.
The question we'd been asked to demonstrate was, is there really a benefit, is it superior, to update the vaccine with the Omicron-containing booster? I think the data as we have here clearly shows that. It becomes a pretty straightforward process of, having now that we've met all of those primary and secondary endpoints, that we need to provide the filings, to the FDA and regulators across the globe. With this data, but having had those initial exchanges with them on the design of the protocol and the criteria for success here, we expect those to be relatively straightforward discussions and submissions. We've been working on those, contemporaneously, and so we've been working on them throughout. We expect to be able to submit them in just a few weeks here.
We're looking forward to that VRBPAC on the June 28th that you're referencing. That VRBPAC has been called by FDA in the United States to make recommendations based on strain and sequence of whether or not it's necessary to update the vaccines, and if so, towards what. You know, we feel strongly the data we have shows that it is appropriate. In fact, we think strongly desirable to update the sequence of the vaccine with an Omicron-containing variant because of the ability to achieve significantly higher titers, which we think will correlate with better durability and better protection against Omicron and subvariants throughout the winter. Those, we've been invited to provide a brief update. The VRBPAC meeting on the twenty-eighth is not around our product.
It is around sequence change, and so we'll be looking forward to sharing this data and other data that emerges over the next few weeks, with the VRBPAC as they make their deliberations and decision on behalf of the United States. Similar exchanges are going on, though not through advisory committees globally with other health authorities, where we are providing them this information real time, alongside our submissions, so that everybody can make the best decisions about what is the best updated booster we can have for the fall this year. We are looking to complete those exercises, as I said, over the next few weeks. In terms of availability of the vaccine, we have been working hard to scale up manufacturing throughout the last several months.
We've been, while we haven't guided to the amounts of vaccine that we'll be manufacturing, we are confident that through the next several months of hard work, we will be able to supply substantial large amounts of the updated bivalent booster, hopefully sufficient to meet all demand that's out there for this updated vaccine through the fall season. Stéphane, do you wanna provide any specific comments on manufacturing?
Sure. I mean, on manufacturing, just a few words. You know, we have been getting ready for a typical fall launch like in the seasonal flu, so we want to be ready as early as August to be shipping. What we have done over the last few months is we have been making a lot of mRNA-1273, over half of a component of a product. Now for several weeks we have been making the mRNA-1273.529 component. We're very on track to be able to supply customers across the world with mRNA-1273.214 for the fall.
Great. Thank you so much. Now, next question coming from the line of Matthew Harrison with Morgan Stanley. Your line is open.
Great. Good morning. Thanks for taking the question. I guess in a similar vein is around regulatory requirements because I think that's the big question for everybody. I guess a two-part question on that. The first one is, do you have a sense. Obviously, you picked what I'll call ancestral Omicron, but we know there are a lot of subvariants of Omicron now, and the prevalence of them is quite different than and maybe quite different in the fall. Do you have a sense of how the regulators are going, or are the regulators gonna mandate a certain strain requirement? And if they did, do you think you'd have to run another experiment, or would you be able to just switch out the strain?
Secondly, you didn't address durability here obviously because you don't have that follow-up, but obviously one of the key points of the bivalent is potentially longer durability. Is that gonna be a key component of what the regulators are gonna want to review? Thanks very much.
Yeah. Great questions both. Thank you, Matt. So let me take the first one on Omicron subvariants. That is an emerging field. Omicron has launched its own strains of the SARS-CoV-2 virus, as we all know. We're following that closely. We're gonna be testing our samples across a range of subvariant assays, but it's important to note those assays, we've all lived this, are still research-grade assays, and so there's a high degree of variability in how they're performing. They need to be qualified, compared, and validated so that we can go make informed decisions about the relative performance of the vaccine.
However, the early data that's out there from the academic literature, mostly academic literature with very small sample numbers, suggest that there is a, you know, two to three-fold decrease for some of the most recent strains, BA.4/5, in the level of neutralizing titers from BA.1. There is a chance that there's approximately two or three-fold decrease. We will have to test these samples and see. Now the good news I think here is that the titers that we're achieving, you know, for instance in the all participants groups, the neutralizing titers we're achieving against Omicron are above 3,000. You know, 3,000 is a much larger number even than we were seeing against the ancestral strain out of the phase III study two years ago.
It is, you know, five-fold higher as a reference point than the approximately 600-700 that we were seeing after a third dose of 1273 against Omicron this past winter. We've got five-fold higher neutralizing titers, a very high absolute number at 3,000. Even if you divide that by two to three-fold, we think we're still gonna be in a very comfortable place because of how high those neutralizing titers against ancestral Omicron or BA.1 are now. For that reason, we're pretty confident that this vaccine is gonna provide a benefit, even against the family of Omicron variants that subvariants we're gonna have to test in these research assays.
I think the most important question is, you know, what's available to the tune of hundreds of millions of doses, to provide protection to those who need it this coming fall? I think that's where, there's also a pragmatic factor that'll have to come to play. You know, we're gonna be in a position to deliver very large volumes, as Stéphane said, of, Omicron-updated vaccine, a vaccine that we know can produce, as I said a moment ago, fivefold higher titers than the third dose, you know, levels up to 3,000, and that has much more room to give in terms of dealing with the evolving virus, throughout the potential fall. We think that's the right path.
I mean, this is a clearly superior booster, statistically significantly so, including against Omicron, and we think the right path is to deploy this booster to give us the best immunity and chance we have. Now, you asked a question about regulatory path if there's a call for updating it. There's definitely, I think, going to be an evolution we expect in how SARS-CoV-2 seasonal vaccines are handled. As you know well, as we all know, in case of flu, another respiratory virus that's seasonal, there's generally a strain recommendation made. It tends to be made early in the year, sort of, you know, February, March time horizon, for the coming fall.
You do not need to develop the kinds of data that we've developed here in every case. You know, in this case, this is we've gone and done bivalent vaccines for a while. This is the second time we've been able to demonstrate superiority. We do believe the bivalent provides better breadth and durability, because of the diversity of antigen it's presenting. We've shown that with our prior beta-containing bivalent two one one. We're quite, you know, we do believe that the data started to pull together across our clinical trials that would support more of a flu-like model, where you just select a strain and then rapidly update the manufacturing and do some parallel testing, but ultimately roll forward without having to run these sort of pivotal superiority studies.
Whether that is going to be in play for this fall, which is kind of the subject of your question, I do not know. That's a question for regulators. That will be a big step forward in terms of our ability to rapidly deploy new vaccines and, you know, given the strength of our mRNA platform, we think we will be pretty well-positioned to provide those updates very quickly. But for now, we're working on the established regulatory guidance for what it takes to update the vaccine sequence. That regulatory guidance calls for demonstrating superiority against the variant of concern, and that's what we did here. For now we're gonna, this is the regulatory framework we're working in. Obviously, if there's opportunities to speed things up in the future, we will.
The second question you asked was about durability, and I thank you for making that point. We have achieved superiority at one month, day 29 here. Now we're gonna continue to follow these participants, and so we'll see whether that superiority is still better or the same at three months, day 90, and at six months, day 181. The real goal is to get to that six to nine months duration of protection, which gets you through the whole respiratory virus season, right? I mean, we'd love even longer than that, but really what we need to get to is something that protects us from October to April in the Northern Hemisphere.
The data we have from our prior bivalent vaccine, which we've obviously presented and is publicly available and also published, that bivalent vaccine for 211 showed better durability at six months against the included Beta variant of concern. We have good reason for optimism based on that data to suggest that actually we think that the bivalent Omicron-containing vaccine here, our 214, is gonna have better durability at six months. What we're seeing at this one-month peak titers, while it's really encouraging and already is better, some of that gap will even widen as time plays out.
Now we need to develop the data to see that and know, but it is based on that prior experience, that published data on our bivalent platform, that we're actually pretty confident that this Omicron-containing bivalent will provide protection through the season, unless of course the virus throws us a new curveball, and that we will see good durability, for those who are boosted in September, October, that can last against Omicron for the better part of the winter.
Thanks, Stephen.
Now next question coming from the line of Michael Yee with Jefferies. Your line is open.
Hey, good morning. This is Siddharth [inaudible] from Michael Yee. Can you hear me okay?
Yep.
This is excellent data as we head into the fall boosting season. I had one or two questions. My first question being, you know, Moderna has submitted for approval for a wild type vaccine for the pediatric population under five. What plans do you have to develop a vaccine that's gonna be, you know, Omicron-based or bivalent-based for the pediatric population? Because it seems like, you know, one part of the population's gonna get the, you know, wild type vaccine, which is the peds population, and the other population, which is the adults, seems to be getting, you know, this newer booster dose. Can you kinda give us some insight into that?
That's a great question. Again, it's one that is, you know, beyond Moderna's control. It's really a question for, you know, first and foremost for regulators and then public health officials, how we will deal with this. As a starting point, you're correct. We've submitted for pediatric authorization. There'll be a VRBPAC next week, as has been previously disclosed. We'll be discussing our prototype vaccine in that context. The basis of approval of the prototype vaccine is based on comparison to its prior performance against other prototype. That's, you know, something that, as we've said before, we're very confident that we've met those criteria and we'll go forward.
It's obvious, though, that the virus has evolved in the last two to three years, and we need to update the vaccine. In this case, we're talking about a booster for adults. We are gonna go study a booster dose for Omicron-containing bivalent, so two-on-four, in the pediatric population as well, including the population in our clinical studies. We are gonna go evaluate the booster in that population to try and demonstrate that there's an advantage there as well. Obviously we wanna characterize the safety profile of that. We are also in the pediatric population in that study gonna be looking at a primary series.
We have, you know, we have patients in our under five studies who have received placebo, and we have an opportunity to cross them over and give them a bivalent vaccine. We're gonna be looking at how they perform with Omicron. That'll be our responsibility as a developer to create that data. There's a more general question which you could ask, which I think is really for regulators and public health officials to decide, which is, does it just make sense to update the vaccine broadly, including primary series for young children, once we have an approval of an updated sequence, for instance, this Omicron-containing bivalent two-on-four. And that is actually precedented. If you think about it, that's what happens with the flu vaccine every year.
Seronegative kids who've not previously gotten the flu vaccine get two doses of a flu vaccine, and they don't get the vaccine from 10 years ago or five years ago or two years ago. They get the vaccine from today. That model is a model that we think will, you know, ultimately, be the right model for how we address SARS-CoV-2 as a seasonal virus as we come to live with it, much like flu. The question of when folks are comfortable, particularly regulators and public health officials are comfortable with switching over to that model is really for them, not for us. We will develop the data through clinical trials that provide confidence we can do that.
You know, I personally believe that the data we've already developed across these booster vaccines provides a high degree of confidence that it probably is appropriate to just update the sequence of the vaccine broadly. They are performing as we would expect. The safety profile is consistent, and the immunogenicity against the variant of concern is superior when you better match the sequence of what's actually circulating. I hope that happens sooner rather than later, but obviously that's for public health officials to decide. Paul, do you wanna add anything to that?
Yeah, no, Stephen, thank you. Look, just on the children, 'cause I think it's a very important point. Clearly these youngest kids are unprotected. There's no other option for them today. And you know, caregivers, moms and dads clearly want to get their kids protected. They also act as a reservoir, right, for potential transmission back to older adults. As we've talked to those people and we've talked to population health decision makers, I think what's become clear with the data that Stephen alluded to, very strong safety data, which is so important obviously to parents, caregivers, physicians, excellent antibody data too.
We believe that our, you know, two-shot regimen here, which is simple, easy, very protective, is important now if authorized to get those kids vaccinated so that they can get through the summer and then get back to school protected. We think this will be a very important part of the armamentarium in our fight against this virus in those youngest kids because it will give that simple solution. We think if authorized, get those kids vaccinated now, and then as Stephen says, we can think about updating booster strategies in the latter part of the year. This will be a quick, simple, safe way to protect those children.
Gotcha. Okay. Just to kind of capture all that, you know, basically what you're saying is that there is precedent, according to the flu vaccine, that once you do kind of your, you know, efficacy study in the booster, Omicron-based booster let's say, you don't need to do another efficacy study every year for each different variant that comes out. Is that accurate?
That's correct in the flu precedent. Again, subject to regulators deciding that we're at that stage.
Right.
with SARS-CoV-2.
Right. My next question then comes, when can we expect kind of updated data or some sort of catalyst for that pediatric Omicron or bivalent boosting dose?
Those studies are just starting now. Obviously, we waited till we had the superior data here with two-on-four to initiate them, and we're, you know, we don't have timing on when those will read out. I also think it's important that before we go too far down the path of deciding that data is necessary, we do need to hear from regulators, including the FDA and VRBPAC next week as to whether or not they believe that's necessary or whether they believe or not we've already crossed that threshold such that we should really be updating the vaccine for children as well.
Those are important questions over the next, I'd say two weeks, that'll be answered, that will then determine the size of the studies we need to run and when or whether we need to run them. I think that we should wait till we have those answers before we start sort of specifically planning for when we'll have data on an updated vaccine for pediatrics 'cause it may not be necessary.
Gotcha. Okay. Just a broad-based question. It was noted, I think, in a press release either earlier this week or at the end of last week that countries that have ordered doses will be eligible for the new bivalent Omicron boost. There's said to be a one-for-one exchange. If they have mRNA-1273 boosts left over, they can send it back to Moderna, and Moderna will send an updated booster dose. Is that accurate?
This is Stéphane. This is not accurate. What we announced last week is an agreement with the European Union to delay some of the Q2 shipment of 1273 into Q3 and Q4 shipment of 214. It is not getting vaccine back. It is shipping products that is of a newer version, which makes sense to protect people.
I see. Okay. They ordered mRNA-1273, however, that's no longer gonna happen. They're gonna get the Omicron or bivalent boost in Q3, Q4 instead of the orders for wild type.
Correct. Exactly. That's what, as you can imagine, health ministers want from a public health standpoint to protect people. Given for us, it's the same mass total. As Stephen explained, of 50 mcg , 25 of mRNA-1273, 25 of mRNA-1273.529, the Omicron-containing mRNA. What we want to do is to be a partner of choice to the government and to provide them the tool they need.
Thanks for all my questions. I appreciate it. Good to see you.
Yeah. Thank you.
All right. Bye-bye.
Okay, we will take our last question. Olivia, can you please queue for the last question?
Sure. Our last question coming from the line of Cory Kasimov with J.P. Morgan. Your line is open.
Hey, good morning, guys. Thank you for taking the question. I actually have two of them for you. First, can you clarify the comments on superiority versus non-inferiority in the study? Because I'm getting some investor questions where there's some confusion if it's a statistically significant superior result or numerically superior. Any clarity there could help. My other question is, do these results impact how you think about the potential privatization of the U.S. market this fall? I mean, was the government waiting to see these data prior to determining a path forward, or is that more driven by the evolution of the virus and pandemic itself? Thanks a lot.
Thank you, Cory, for the clarifying questions. I'll let Stéphane take the second half with Paul if he wants. First on the superiority. Unequivocally, these are statistically significantly superior for Omicron and the ancestral strain. I think if I was confusing in my framing of that, we tested non-inferiority, and then we tested superiority. In terms of neutralizing antibody titers, the primary endpoint for demonstrating superiority, we were significantly superior against Omicron and incidentally significant against the ancestral strains, although that's not of substantial importance. The only place where I might have confused a little bit is in describing the seroresponse rate. Seroresponse rate is just the number of people who had a response. People have a response even to the prototype vaccine, so it's near 100% in both cases.
We were not specifically trying to demonstrate superiority there ever. That was not an objective, nor is it necessary to demonstrate superiority there. Unequivocally, the results are statistically significantly superior on neutralizing titers against Omicron, which is the primary endpoint for demonstrating superiority against that variant of concern that was established with regulators.
Okay. Very helpful.
Cory, Stéphane for the second question. I don't think this has anything to do with authorization. It is really linked to funding from Congress. As you can imagine, we have shared with the U.S. government and the regulators of course, but all the key public health leaders in the U.S. government, the 211 data, when we had it, as you remember a couple months ago. Of course, I think sharing that data, I think the opinion in the U.S. has been exactly the same thing we've heard outside the U.S., which is as people see the data, they are very interested to get this product bivalent versus the ancestral vaccine. The authorization for me is really driven by the funding in Congress.
Okay, great. Thank you very much. Appreciate it.
Thank you.
Thank you. I will now turn the call back over to Mr. Stephen Hoge for any closing remarks.
Thank you, operator. Well, thank you all for joining and listening. I think, we believe the data unequivocally shows the bivalent Omicron containing booster is significantly superior in terms of neutralizing protection. It more accurately reflects the circulating strain, and the data clearly shows it's time to update the vaccine so we can improve the durability of protection, the magnitude of protections coming into the fall. We'll look forward to meeting with regulators. Thank you all for taking time this morning to review it with us, and have a good morning and good afternoon.
Ladies and gentlemen, that does end our conference call today. Thank you for your participation. You may now disconnect.