Sanofi SNY announced that the FDA has granted a fast-track designation to its mRNA vaccine candidate for the prevention of chlamydia infection.

The company plans to begin a phase I/II study soon, which will evaluate the immunogenicity and safety of the vaccine candidate in adults aged between 18 and 29 years.

Sanofi decided to begin the phase I/II study after the chlamydia vaccine candidate demonstrated promising results in pre-clinical studies.

Caused by the bacterium Chlamydia trachomatis, chlamydia is a common bacterial infection of the reproductive tract that can lead to infertility and pregnancy complications.

The vaccine candidate is being developed to protect against primary genital tract infection and reinfection by the bacterium.

SNY's Price Performance

Shares of Sanofi have rallied 15% year to date compared with the industry’s increase of 4.5%.

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SNY Boasts a Strong Vaccine Segment

Sanofi possesses one of the world’s leading vaccine operations, with total annual sales of more than €5 billion in the past five years.

The company’s Vaccines unit has delivered mid-to-high-single-digit sales growth since 2018. In 2024, Sanofi’s Vaccines segment recorded sales growth of 13.5% at a constant exchange rate, exceeding management’s expectations.

Sanofi continues to expand its vaccine business further. The company has multiple vaccine candidates, which are expected to enter phase III development by 2025. Some vaccine candidates that are already in phase III development include a 21-valent pneumococcal conjugate vaccine and a next-generation rabies vaccine.

Sanofi expects its annual net sales to be more than €10 billion from its Vaccines unit by 2030, backed by its innovation efforts.

The successful development of the chlamydia vaccine should diversify SNY’s vaccine business, as there remains an unmet medical need to address this serious condition, particularly when treatment with antibiotics has not been able to control rising infection rates.

SNY's Zacks Rank & Stocks to Consider

Sanofi currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are Gilead Sciences, Inc. GILD and Krystal Biotech, Inc. KRYS, each carrying a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

In the past 60 days, estimates for Gilead’s earnings per share have increased from $7.53 to $7.87 for 2025. During the same time, earnings per share estimates for 2026 have increased from $7.76 to $8.27. Year to date, shares of GILD have increased 16.8%.

GILD’s earnings beat estimates in each of the trailing four quarters, the average surprise being 19.47%.

In the past 60 days, estimates for Krystal Biotech’s earnings per share have increased from $5.50 to $7.06 for 2025. During the same time, earnings per share estimates for 2026 have increased from $9.15 to $11. Year to date, shares of KRYS have rallied 22.8%.

KRYS’ earnings beat estimates in three of the trailing four quarters while missing the same on the remaining occasion, the average surprise being 3.29%.

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This article originally published on Zacks Investment Research (zacks.com).

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