ABSTRACT
Immune escape is observed with SARS-CoV-2 Omicron (Pango lineage B.1.1.529), the predominant circulating strain worldwide. A booster dose was shown to restore immunity against Omicron infection; however, real-world data comparing mRNA (BNT162b2; Comirnaty) and inactivated vaccines' (CoronaVac; Sinovac) homologous and heterologous boosting are lacking. A retrospective study was performed to compare the rate and outcome of COVID-19 in healthcare workers (HCWs) with various vaccination regimes during a territory-wide Omicron BA.2.2 outbreak in Hong Kong. During the study period from 1 February to 31 March 2022, 3167 HCWs were recruited, and 871 HCWs reported 746 and 183 episodes of significant household and non-household close contact. A total of 737 HCWs acquired COVID-19, all cases of which were all clinically mild. Time-dependent Cox regression showed that, compared with two-dose vaccination, three-dose vaccination reduced infection risk by 31.7% and 89.3% in household contact and non-household close contact, respectively. Using two-dose BNT162b2 as reference, two-dose CoronaVac recipient had significantly higher risk of being infected (HR 1.69 p < 0.0001). Three-dose BNT162b2 (HR 0.4778 p< 0.0001) and two-dose CoronaVac + BNT162b2 booster (HR 0.4862 p = 0.0157) were associated with a lower risk of infection. Three-dose CoronaVac and two-dose BNT162b2 + CoronaVac booster were not significantly different from two-dose BNT162b2. The mean time to achieve negative RT-PCR or E gene cycle threshold 31 or above was not affected by age, number of vaccine doses taken, vaccine type, and timing of the last dose. In summary, we have demonstrated a lower risk of breakthrough SARS-CoV-2 infection in HCWs given BNT162b2 as a booster after two doses of BNT162b2 or CoronaVac.
ABSTRACT
Pulmonary fibrosis (PF) is a restrictive lung disease that may occur idiopathically or as a complication of many diseases. The outcome of the current treatment by glucocorticoids remains very unsatisfactory. This study has tested a new Chinese medicine formula DSQRL for the treatment of experimental PF in comparison with prednisone. Seventy-two rats with PF induced by CCl(4) were randomly divided into four groups to undertake the treatment of either (a) high dose of prednisone; (b) Chinese medicine formula DSQRL; (c) combined treatment of the above two; or (d) tap water of the same volume. At the end of 30 days treatment, the DSQRL treatment achieved a better outcome (p<0.05) than prednisone in terms of histological examination, bronchoalveolar lavage fluid analysis, hydroxyproline assay and complications. The observations support further investigation and clinical trials of this Chinese medicinal formula for the treatment of PF.
