Vaccine stocks have been under significant pressure in recent days following news that the FDA director who oversaw the agency's vaccine program has resigned over concerns that newly appointed HHS officials were promoting misinformation about immunizations. 

Seeking Alpha analysts Stephen Ayers and Terry Chrisomalis weigh in on how management changes at the agency could impact vaccine makers.

Stephen Ayers: Dr. Peter Marks' (a top vaccine regulator) resignation signals that the Trump administration means business - for better or worse. It creates uncertainty and the market hates that! Notably, Moderna’s (NASDAQ:MRNA) 9% haircut on Monday spoke volumes. The company has two FDA-approved vaccines and is awaiting word on a few more. 

If regulators increase scrutiny of vaccines, as HHS secretary Robert F. Kennedy Jr. has alluded to in the past, this could have major repercussions for vaccine developers. Companies like Moderna (NASDAQ:MRNA) spend years playing by the rules of the FDA. If authorities change the rules mid-game, it’ll be challenging for drug developers to come out on top. 

Specifically, data requirements may tighten. This could involve longer safety follow-ups or more people tested prior to approval. Either way, you’re extending the development timeline. Regulatory applications could face intense scrutiny and be rejected for even minor concerns, pushing back commercialization. 

It also creates a “snowball effect,” particularly for mRNA-focused companies like Moderna (MRNA), Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX). The public is already wary of mRNA technology. Increased scrutiny from authorities on the issue could exacerbate negative public perceptions and influence healthcare decisions. 

All in all, these developments may impact the entire lifecycle of vaccines (clinical development, regulatory approval and market adoption).

Terry Chrisomalis: In my opinion, I don’t think there will be a long-term impact on stocks such as Moderna (MRNA), Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX), just to name a few. The reason why is that there have been no sweeping statements made as of yet as to what changes will be made. What might cause an issue for companies like Johnson & Johnson (NYSE:JNJ), Merck (NYSE:MRK), Sanofi (NASDAQ:SNY), AstraZeneca (NASDAQ:AZN) and GlaxoSmithKline (NYSE:GSK) would be tariffs potentially being levied on vaccines, which hasn’t been done before.