Impact of COVID-19 Vaccination on Healthcare Worker Infection Rate and Outcome during SARS-CoV-2 Omicron Variant Outbreak in Hong Kong.

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.

Are There Differences in Antibiotic Use Between the Recent-Immigrants from Mainland China and the Local-Born in Hong Kong?

Immigrants, especially the first-generation, were thought to have different knowledge, attitudes and practice (KAP) with antibiotics. Doctors often perceived extra pressure from them to prescribe antibiotics. To test these perceptions, we studied the difference in KAP with antibiotics between the recent-immigrants from mainland China and the local-born of Hong Kong-places with significantly different healthcare and socio-economic systems. Focus groups (including one specific group of recent-immigrants) with 56 participants and territory-wide telephone questionnaire survey with 2,471 randomly selected respondents. Recent-immigrants shared similar KAP with the local-born. After adjustment for age, sex and education, the main significant difference was the new-immigrants' behaviour of acquiring antibiotics without prescription and keeping the leftover. They, like the local-born, preferred doctors who prescribed antibiotics cautiously. Immigration status could be the surrogate for age, sex and education in the KAP with antibiotics. For antibiotic use, health education and patient care could be similar between the recent-immigrants and the local-born.

The public's perspectives on antibiotic resistance and abuse among Chinese in Hong Kong.

PURPOSE: Antibiotic abuse and resistance impose a continuing threat to the world. The awareness of antibiotic resistance is said to be inversely associated with the prevalence of abuse. We examined the public's perspectives on antibiotic resistance in our study of the public's knowledge, attitude and practice with antibiotics. METHODS: The study adopted a combined qualitative and quantitative approach. Eight focus groups were conducted with 56 participants purposively selected from community centres and of different socio-economic strata. The qualitative data collected were used to construct a questionnaire for the telephone survey which surveyed 2471 adults from randomly selected residential numbers. RESULTS: The focus-group participants were unclear about the nature and causes of antibiotic resistance; they also attributed antibiotic abuse to the doctors' responsibility. Of the questionnaire respondents, 9.0% had not heard of the term, 7.8% had ever acquired non-prescribed antibiotics, 6.6% had ever kept the leftover and only 69.8% had always finished the full course of antibiotics. Furthermore, 77.3 % and 75.1%, respectively, agreed that the purchase of antibiotics without prescription and incomplete courses of antibiotics would lead to undesirable consequences. Of the respondents who had heard about antibiotic resistance, 38.7% agreed that they could help the prevention of resistance. They were more likely to complete the full course of antibiotics and less likely to keep the leftovers. CONCLUSIONS: The public in general was not aware of the causes of, nor their role and capability in preventing, antibiotic resistance. Future campaigns and health education should empower everyone to restrain antibiotic resistance.