An Ulster County resident who was vaccinated against COVID-19, but tested positive for the delta variant of the virus, is the first known “breakthrough case” of the delta variant in the county.

County Executive Pat Ryan said the infected resident has recovered and was spared from the worst effects of the variant, likely because the resident was fully vaccinated.

Studies have found the two-shot Pfizer vaccine is 88% effective against delta, and 96% of those infected do not require hospitalization.

Moderna executives said Tuesday that lab results indicated their two-shot vaccine reacted similarly to the delta variant as it did the original strain.

Less data is available on the one-shot Johnson & Johnson vaccine’s efficacy against delta, a strain 40% to 60% more transmissible than the Alpha variant.

The strain is 40% to 60% more transmissible than the original virus.

Ryan said he hopes this development gives unvaccinated people a nudge to get the shots.

“For me, the big takeaway from the delta variant is, if we can get to full vaccination, it can really slow the ability of any variant, delta or otherwise, to spread,” Ryan said during an interview in his office Tuesday. “To me, this news really should be a reminder that we’re not through this, and really the only way through this is to get everyone fully vaccinated.”

Ryan said that while 73% of all adults in Ulster County have been fully vaccinated, county health officials want that number higher.