Canine distemper virus (CDV) poses a substantial threat to diverse carnivores, leading to sys-temic and often fatal diseases. Accurate and prompt diagnosis is paramount for effective man-agement and curbing further transmission. This study evaluates the diagnostic efficacy of drop-let digital PCR (ddPCR) in comparison to conventional reverse transcription (RT-PCR) and quantitative reverse transcription real-time PCR (RT-qPCR). Seventy-six clinical samples were collected from dogs with CDV symptoms diagnosed by specialized veterinarians, and sixteen samples from asymptomatic individuals. Conventional PCR, quantitative real-time PCR, and ddPCR were deployed, and their diagnostic capabilities were meticulously assessed. DdPCR ex-hibited heightened analytical sensitivity, reaching a detection limit of 3 copies/μL, whereas RT-qPCR had a detection limit of 86 copies/μL. The comparative analysis between clinical diagnosis and molecular techniques, including RT-PCR and RT-qPCR, demonstrated low concordance, with Kappa coefficients of 0.268 and 0.324, respectively. In contrast, ddPCR, showed a moderate concordance, with a Kappa coefficient of 0.477. Sensitivity was 42.39% for RT-PCR, 57.89% for RT-qPCR and 72.37% for ddPCR, with 100% of specificity for all methods. This study under-scores ddPCR's superior sensitivity and concordance with clinical CDV diagnosis, even at low viral concentrations, suggesting it as a promising alternative for CDV diagnosis.

The SARS-CoV-2 Omicron variant and its sublineages continue to cause COVID-19—associated pediatric hospitalizations, severe disease, and death globally. BNT162b2 and CoronaVac are among the top most widely used COVID-19 vaccines. Much less is known on the Wuhan-Hu-1 strain based vaccines in the pediatric population compared to adults. Given the worldwide need for booster vaccinations to stimulate the immune response against new Omicron variants of SARS-CoV-2, we characterized the humoral and cellular immune response against Omicron variant BA.1 in a pediatric population aged 10 to 16 years who received heterologous vaccination based on two doses CoronaVac, two doses CoronaVac (2x) plus one booster doses BNT162b2 [CoronaVac(2x) + BNT162b2 (1x)], two doses CoronaVac plus two booster doses BNT162b2 [CoronaVac(2x) + BNT162b2 (2x)], and three doses BNT162b2. We observed that [CoronaVac(2x) + BNT162b2 (2x)] vaccination showed higher anti-S1 and neutralizing antibody titers and CD4 and CD8 T cell immunity specific to the Omicron variant compared to immunization with two doses CoronaVac alone. Furthermore, from all groups tested, immunity against Omicron was highest in individuals who received three doses BNT162b2. We conclude that booster vaccination with BNT162b2 promotes greater immunity against SARS-CoV-2 in the pediatric population compared to two doses CoronaVac alone.