(Bloomberg) -- Johnson & Johnson halted development of a vaccine for respiratory syncytial virus infections in adults, leaving a $10 billion market to competitors who are ahead in their efforts.

J&J decided to discontinue its program after assessing the RSV vaccine landscape, the company said. The decision isn’t a surprise to analysts, who said safety concerns over J&J’s vaccine platform appeared to slow recruitment for clinical trials and might limit its use in the market.

Wall Street had estimated J&J could generate sales of $975 million by 2028, Bloomberg Intelligence analyst John Murphy said Wednesday in a note, calling the announcement “a setback.” J&J’s RSV vaccine used an adenovirus-based delivery system. The company used the same system for its Covid-19 shot, which saw demand wane due to rare incidents of blood clotting.

J&J shares were up about about 1% to $153.26 at 11:13 a.m. in New York.

RSV is a common virus that causes lung infections, and it can be especially dangerous for infants and older adults. Health professionals have long hoped for tools to temper seasonal surges, but until recently past failures had kept companies from wading into the market. 

Sales of vaccines for adults over age 60 could approach $10 billion by 2032, analysts say, with GSK Plc, Pfizer Inc. and Moderna Inc. dominating the market.

Vaccines made by Pfizer and GSK recently won support from a key panel of advisers to the US Food and Drug Administration, setting up a race to approval. Moderna has completed phase 3 studies of its adult RSV candidate.

The FDA advisers had concerns over rare side effects seen in both Pfizer and GSK’s shots and a lack of data on hospitalizations in the adults over 80, vaccine durability and co-administration with other vaccines. 

Next week, Pfizer, GSK and Moderna will discuss their RSV candidates during a four-day vaccine congress in Washington, including Moderna’s efforts toward a messenger RNA-based shot. Bavarian Nordic A/S is also slated to present data on its vaccine, which is behind others in the development process, but analysts think it could exceed expectations. 

J&J still plans to share the results of its RSV trial with the scientific community, a spokesperson said in an email.

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