A few years ago, when the coronavirus pandemic was still high, any positive news from a COVID-19 vaccine or drug developer would have led to a rush to buy stocks. However, we are no longer in 2021, and an encouraging development from Pfizer (PFE -1.43%) When the company announced a combined COVID/flu vaccine, the market reacted with a collective shrug. In fact, investors sold the stock so much that its price fell by 1.4%, which was unfavorable compared to the 0.2% increase in the share price. S&P500 Index per day.

Combination vaccine fails in clinical trial

Before the market opening, Pfizer and BioNTechthe co-developer of the hugely popular Comirnaty COVID vaccine, has released an update on this combination vaccine.

A Phase 3 clinical trial in patients ages 18 to 64 met one of its two primary endpoints, with the combination vaccine successfully achieving immunogenicity against the SARS-CoV-2 virus strain that causes COVID, but failed to do so against either influenza A or influenza B, as it elicited an inadequate immune response against the latter. In their joint press release, the companies quoted Pfizer’s head of vaccine research, Annaliesa Anderson, as saying:

Our goal is to develop vaccines to reduce the burden of respiratory disease and we believe that combination vaccines are the most effective way to do this. Today’s results provide insight into our progress towards this goal and provide direction. We remain optimistic about our combined COVID-19 and influenza program, for which we are currently evaluating next steps.

Back to the drawing board

The modest sell-off suggested that investors like the two companies see enough positive results in advanced testing not to give up hope in the combination vaccine. COVID is still a threat and flu is a constant health scourge, so if Pfizer and BioNTech can eventually develop an effective two-for-one shot, it would almost certainly prove to be a very popular shot.