Immunogenicity and reactogenicity of heterologous immunization schedules with COVID-19 vaccines: a systematic review and network meta-analysis.

BACKGROUND: Data on the immunogenicity and safety of heterologous immunization schedules are inconsistent. This study aimed to evaluate the immunogenicity and safety of homologous and heterologous immunization schedules. METHODS: Multiple databases with relevant studies were searched with an end date of October 31, 2021, and a website including a series of Coronavirus disease 2019 studies was examined for studies before March 31, 2022. Randomized controlled trials (RCTs) that compared different heterologous and homologous regimens among adults that reported immunogenicity and safety outcomes were reviewed. Primary outcomes included neutralizing antibodies against the original strain and serious adverse events (SAEs). A network meta-analysis (NMA) was conducted using a random-effects model. RESULTS: In all, 11 RCTs were included in the systematic review, and nine were ultimately included in the NMA. Among participants who received two doses of CoronaVac, another dose of mRNA or a non-replicating viral vector vaccine resulted in a significantly higher level of neutralizing antibody than a third CoronaVac 600 sino unit (SU); a dose of BNT162b2 induced the highest geometric mean ratio (GMR) of 15.24, 95% confidence interval [CI]: 9.53-24.39. Following one dose of BNT162b2 vaccination, a dose of mRNA-1273 generated a significantly higher level of neutralizing antibody than BNT162b2 alone (GMR = 1.32; 95% CI: 1.06-1.64), NVX-CoV2373 (GMR = 1.60; 95% CI: 1.16-2.21), or ChAdOx1 (GMR = 1.80; 95% CI: 1.25-2.59). Following one dose of ChAdOx1, a dose of mRNA-1273 was also more effective for improving antibody levels than ChAdOx1 (GMR = 11.09; 95% CI: 8.36-14.71) or NVX-CoV2373 (GMR = 2.87; 95% CI: 1.08-3.91). No significant difference in the risk for SAEs was found in any comparisons. CONCLUSIONS: Relative to vaccination with two doses of CoronaVac, a dose of BNT162b2 as a booster substantially enhances immunogenicity reactions and has a relatively acceptable risk for SAEs relative to other vaccines. For primary vaccination, schedules including mRNA vaccines induce a greater immune response. However, the comparatively higher risk for local and systemic adverse events introduced by mRNA vaccines should be noted. REGISTRATION: PROSPERO; https://www.crd.york.ac.uk/PROSPERO/ ; No. CRD42021278149.

Study on the protective effect of the cichoric acid to piglet infected with porcine deltacoronavirus

To evaluate the protective effect of cichoric acid against PDCoV, 36 8-day-old suckling piglets were randomly divided into 4 groups in this study, with 9 pigs in each group. Each piglet in the cichoric acid group and cichoric acid+challenge group was given orally cichoric acid (3.6 mg/kg body weight) every day;on the 3rd day of the experiment, each piglet in the challenge group and the cichoric acid+challenge group was orally administered 10mL of PDCoV NC isolate (10~5TCID50/mL) for challenge, while each piglet in the blank group and cichoric acid group was orally administered 10mL DMEM;on the 7th day, all piglets were subjected to necropsy. Statistics analysis was performed for the average daily weight gain and the degree of diarrhea in piglets in each group, and the results showed that during the experiment, the diarrhea degree of the piglets in the challenge group was more serious than that in the cichoric acid+challenge group, and the average daily gain of the piglets in the challenge group was significantly lower than that in the cichoric acid+challenge group, control group and cichoric acid group (P<0.05), while the average daily gains of cichoric acid+challenge group, control group and cichoric acid group have no significant difference. Pathological and histopathological examinations showed that the small intestinal tissue lesions of the piglets in the challenge group were more serious than those in cichoric acid+challenge group, and a large number of intestinal villi were shed. The real time PCR was used to detect the PDCoV load and the amount of antiviral gene in the small intestine of piglets in each group, results showed that compared with the challenge group, the amounts of antiviral genes OAS,Mx1 and PKR in the jejunum and ileum of the cichoric acid+challenge group were increased, while the PDCoV were decreased significantly. The above results indicate that the damage of PDCoV to the intestinal tract caused by PSCoV was reduced for the piglets given orally cichoric acid. This study first reported that cichoric acid has a protective effect on the piglets with PDCoV challenge, providing theoretical basis for the studies of cichoric acid's antiviral mechanism and clinical prevention and control of PDCoV.