The stock market closed the week on a positive note, and vaccine stocks helped lead the way higher. Friday's gains for the Dow Jones Industrial Average (^DJI 0.04%), S&P 500 (^GSPC -0.16%), and Nasdaq Composite (^IXIC -0.18%) all topped the 1% mark, although all three finished down for the week.

Index

Daily Percentage Change

Daily Point Change

Dow

+1.26%

+402

S&P 500

+1.36%

+51

Nasdaq

+1.28%

+132

Data source: Yahoo! Finance.

Shares of Moderna (MRNA -0.74%) and BioNTech (BNTX -1.44%) gained 7% and 6%, respectively, on Friday. Both vaccine stocks benefited from several pieces of news that could give them another lift in COVID-19-related sales. But that still leaves a key question for investors: Can COVID-19 vaccines alone keep supporting vaccine stocks' price levels, or will these companies, which generated so much success during the first two years of the pandemic, need to find other growth drivers to keep up their momentum?

BioNTech scores big wins

A lot of the positive news Friday was specific to BioNTech. Along with its partner, Pfizer (PFE), BioNTech released data from a phase 2/3 clinical trial that showed a robust neutralizing immune response one month after the administration of a 30-microgram dose of its bivalent omicron BA.4/BA.5 COVID-19 vaccine.

The data was particularly noteworthy because it confirmed the value of getting inoculated with the latest bivalent vaccines, even for people who were vaccinated with previous iterations of the shots earlier in the pandemic. BioNTech said that the immune responses of subjects in the trial were substantially higher against those omicron variants than those generated by its own original COVID-19 vaccine.

The study's findings also show a path forward for new COVID-19-related development. As BioNTech co-founder and CEO Uğur Şahin noted, the company's aim is to learn more about the coronavirus to determine whether it can cross-neutralize new variants, potentially getting ahead of future outbreaks before they occur.

In addition, BioNTech's COVID-19 vaccine will now be available to foreigners who are living in China. The deal, brokered by German Chancellor Olaf Scholz, could be a first step toward making BioNTech's vaccine available to Chinese citizens as well. Until now, China has provided only domestically produced vaccines to its own people.

Moderna bounces back

Moderna has made its own bivalent omicron-specific COVID-19 vaccine, so it makes sense that investors would draw similar conclusions about its prospects. Yet Moderna stock has seen considerable volatility in the past couple of days, starting with the response to its release of third-quarter financial results.

As expected, Moderna's financial numbers dropped precipitously, with product sales falling 35% year over year and earnings plunging 67% to $2.53 per share. At the same time, the company is working hard to develop its pipeline of candidate treatments, and while that could bring good news in the long run, it means more immediate increases in clinical trial and drug development costs that will weigh even more heavily on its bottom line.

Yet after dropping nearly 10% early Thursday, Moderna stock recovered nearly all of its losses by the end of that day's session, setting the stage for Friday's further gains. That indicates some confidence that Moderna's other developmental programs will eventually bear fruit.

Keep your eye on vaccine stocks

If China opens its market to the COVID-19 vaccines produced by BioNTech and Moderna, those two companies could get one final dose of revenue growth. Yet in the long run, the prospects for these two stocks will rely on whether they can use their technology to come up with treatments or vaccines for other diseases -- and successfully commercialize them in the way they did their COVID-19 products.