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Vaccine makers have set their eyes on the next big thing: Developing combination shots targeting both Covid and the flu.

As Covid vaccination rates in the U.S. dwindle, Pfizer, Moderna and Novavax, among other companies, hope that more convenient combo shots offering protection against two viruses rather than one will increase uptake among Americans. Some health experts have cast doubt on that belief, CNBC previously reported. 

Still, combo jabs may also reduce the burden that respiratory viruses — which typically spread at the same time each year — put on pharmacists and the broader U.S. health-care system. 

The race to develop those jabs is heating up, as all three companies test their respective vaccines in mid- or late-stage trials. 

But Pfizer and its German partner BioNTech faced a setback last week that may allow rival Moderna to pull ahead. 

Pfizer on Friday said its messenger RNA-based vaccine that combines its approved Covid shot with an experimental flu shot failed to meet one of the main goals of a phase three trial on more than 8,000 adults, potentially jeopardizing the jab's future. 

The vaccine produced a more effective immune response against influenza A strain than a licensed flu vaccine and was as effective against Covid as Pfizer's existing product. But the shot showed a weaker immune response against another flu strain called influenza B compared with the licensed flu vaccine. 

Pfizer and BioNTech will consider adjustments to the combo shot and "discuss next steps with health authorities," according to a release.

"We remain optimistic about our combination COVID-19 and influenza program, for which we are evaluating the next steps," Annaliesa Anderson, Pfizer's head of vaccine research and development, said in the release. 

Mikael Dolsten, Pfizer's outgoing chief scientific officer, said at a conference in March that the company hopes to launch its combination shot in 2025. It's unclear whether Friday's results change that timeline. 

If it does, that could be good news for Moderna. The biotech company's mRNA-based combination shot succeeded in a late-stage trial in June, showing higher immune responses than existing standalone shots for Covid and the flu. 

Moderna plans to file for regulatory approval for that shot and hopes it can enter the market in 2025. 

"Failure of this [Pfizer and BioNTech] combo vaccine study puts [Moderna] in the lead in the mRNA combo vaccine development," Leerink Partners analyst David Risinger said in a note Friday, adding that Pfizer's "update incrementally improves the odds that [Moderna's shot] could be the first commercially available combo mRNA vaccine."

Pfizer's stumble could also be good news for Novavax and Sanofi, which partnered earlier this year to develop protein-based combination Covid and flu shots. In May, Sanofi, a top flu shot maker, agreed to pay Novavax up to $1.2 billion up front and future milestones in part to work on combining the companies' vaccines. 

Still, there is a chance that Pfizer could make the right tweaks to its vaccine to get it back on track toward regulatory approval. For example, Moderna's initial standalone flu vaccine similarly failed to show an immune response as effective as an approved vaccine against influenza B before the company made adjustments to overcome that setback. 

We'll be watching closely for any updates in the combination shot space, so stay tuned.

Feel free to send any tips, suggestions, story ideas and data to Annika at annikakim.constantino@nbcuni.com.

Latest in health-care tech: Epic's UGM meeting is underway – here's what to expect

This is Ashley, reporting live from Verona, Wisconsin!

I'm here attending Epic Systems' annual Users Group Meeting, or UGM, for the first time, and it's sure to be an eventful day. 

Epic is a health-care software giant whose technology is used in thousands of hospitals and clinics across the country. Its 1,670-acre headquarters is nestled about 30 minutes away from Madison, and thousands of health-care leaders are gathered here to talk tech this week.

The main event will be Tuesday's executive address, where Epic's CEO Judy Faulkner and other senior leaders will share updates about the company's latest initiatives. It takes place in a partially underground auditorium called "Deep Space," which can seat more than 11,000 people. 

Deep Space is a central fixture of Epic's notoriously quirky campus, which is adorned with statues of wizards and buildings themed like "The Wizard of Oz" and "Alice in Wonderland." Don't worry, I'm going on a guided tour this afternoon, so I'll have much more to share about this soon. 

But if that isn't enough to pique your interest, Epic executives will also deliver the address in costume. The theme of this year's UGM is "Storytime," according to the company's website. Remember this next time anyone tries to tell you health care is boring. 

As far as announcements go, I expect we'll hear a lot about Epic's work to integrate artificial intelligence into its software. The company already has more than 60 AI development projects underway, according to its website, and its high-profile partnerships with AI scribing companies such as Abridge and Microsoft's Nuance Communications have generated a lot of industry chatter this year. 

Perhaps unsurprisingly, both Nuance and Abridge are here attending UGM. 

Epic has also made waves in the health-tech interoperability space this summer. The company is one of the organizations that's been helping the federal government establish the Trusted Exchange Framework and Common Agreement, or TEFCA, to provide a legal and technical framework for securely sharing patient data.

Epic said Friday that it's planning to move all of its customers to TEFCA by the end of next year. It's a big move: Because of Epic's dramatic reach and its 45-year history on the market, the company's commitment to TEFCA will likely bolster the exchange's credibility. 

I would bet Epic's leadership will touch on these efforts, as well as other ways the company is working to leverage its vast network. 

Stay tuned for lots more UGM content from me this week! And if you have tips about where I can track down the best cheese curds on campus, please get in touch. 

Feel free to send any tips, suggestions, story ideas and data to Ashley at ashley.capoot@nbcuni.com.