What happened

It's always tough when a company announces a piece of good news but is eclipsed by far better developments from a peer. This was the case with high-profile biotech Moderna (MRNA 1.52%) on Wednesday. As a result, the company's shares declined marginally, while the S&P 500 index closed the day nearly 2% higher.

So what

Moderna's positive news came from across the Atlantic Ocean, where the European Medicines Agency (EMA) accepted a conditional marketing authorization (CMA) application for the company's bivalent coronavirus booster vaccine. This latest version of the widely administered Spikevax aims to block both the original form of the coronavirus and its omicron variants. The EMA functions as a pharmaceutical industry regulator for the 27-nation European Union.

As with the initial version of Spikevax, take-up throughout the world has been quick. Moderna didn't hesitate to point out that the new booster has already been given the green light by the U.S. Food and Drug Administration (FDA) and a host of other jurisdictions, including Australia, Taiwan, and the U.K.

Now what

But there were two developments that leeched investor optimism. The first was the continued and at times dramatic slides in key statistics for the coronavirus. According to The New York Times' coronavirus tracker, the number of cases has dropped by 21% over the past two weeks, while hospitalizations have declined by 15%, and deaths by 4%.

The second and most immediate is that Biogen and biotechs associated with Alzheimer's disease stole much of the sector's thunder in Wednesday's trading session. Biogen and its partner Eisai announced late Tuesday that their lecanemab Alzheimer's drug met the primary endpoint of a late-stage clinical trial, reducing cognitive decline by almost 30%.

Although Moderna has had its successes, investors are still concerned about the company's post-pandemic future. At the moment, the prospects for Alzheimer's drug manufacturers suddenly looks much more promising.