PDCoV Antibodies Found in 10 US Human Serum Samples

Porcine deltacoronavirus (PDCoV) is a swine coronavirus with potential to cross species barriers. Researchers screened 200 commercially acquired adult serum samples collected in 2021 and 100 samples from juvenile swine exhibitors with daily or near-daily swine contact, collected during 2019–2021. Samples were tested by ELISA, with positive results assessed by virus-neutralization testing.

Ten samples had PDCoV-neutralizing antibodies: 9 of 100 juvenile samples (9.0%) and 1 of 200 adult samples (0.5%). Neutralization titers ranged from 1:80 to 1:320. Seropositivity was more frequent among juvenile exhibitors than adults, but the groups differed in age, source population and exposure information. Swine-contact histories were unavailable for adult donors.

The results provide serologic evidence consistent with human exposure, particularly among juveniles who frequently had contact with swine. Antibodies indicate previous exposure but do not establish active infection, clinical disease or human-to-human transmission. The authors caution that convenience sampling, limited epidemiologic data, uneven geographic representation and the absence of validated human positive controls prevent estimates of population prevalence or transmission risk. They call for further serologic and virologic surveillance; the public health implications remain unclear.