Analysis of the Effectiveness of Measures on the COVID-19 Vaccination Rate in Hong Kong

Assessment of the impact of the vaccine pass policy on COVID-19 vaccine hesitancy and uptake among Chinese adults in Hong Kong

BACKGROUND

Recognising the importance of attaining high vaccine coverage to mitigate the COVID-19 impact, a Vaccine Pass scheme was implemented during and after the first large Omicron wave with high mortality in older ages in Hong Kong in early 2022 requiring three doses by June 2022. We did not identify any studies evaluating the policy impact of vaccination mandates with vaccine uptake over whole policy period of time in a Chinese population. We aim to evaluate the impact of the Vaccine Pass policy on COVID-19 vaccine uptake in adults in a Chinese population in Hong Kong.

METHODS

We analysed patterns in vaccine uptake and hesitancy using local data from population vaccine registry and 32 cross-sectional telephone surveys conducted from October 2021 to December 2022. The association of Vaccine Pass phases with vaccine uptake was examined using logistic regression analyses, taking into account covariates including self-risk perception, perceived self-efficacy in preventing COVID-19 and trust in government in pandemic control as well as physical distancing measures and demographics.

RESULTS

The uptake of primary series and third doses was positively significantly associated with the successive stages of Vaccine Pass implementation (adjusted odds ratios ranged from 2.41 to 7.81). Other statistically significant drivers of uptake included age group, chronic condition, higher perceived personal susceptibility to COVID-19, higher trust in government, and higher educational attainment.

CONCLUSION

Vaccine uptake in older adults was observed to have increased by a greater extent after the policy annoucement and implementation, under the contextual changes during and after a large Omicron wave with high mortality in Hong Kong in early 2022. Since the policy withdrawal the uptake of further booster doses has been very low in all ages. We suggest that improving voluntary booster uptake in older adults should be prioritized.

A global scale COVID-19 variants time-series analysis across 48 countries

Background

The coronavirus disease (COVID-19) pandemic is slowing down, and countries are discussing whether preventive measures have remained effective or not. This study aimed to investigate a particular property of the trend of COVID-19 that existed and if its variants of concern were cointegrated, determining its possible transformation into an endemic.

Methods

Biweekly expected new cases by variants of COVID-19 for 48 countries from 02 May 2020 to 29 August 2022 were acquired from the GISAID database. While the case series was tested for homoscedasticity with the Breusch-Pagan test, seasonal decomposition was used to obtain a trend component of the biweekly global new case series. The percentage change of trend was then tested for zero-mean symmetry with the one-sample Wilcoxon signed rank test and zero-mean stationarity with the augmented Dickey-Fuller test to confirm a random COVID trend globally. Vector error correction models with the same seasonal adjustment were regressed to obtain a variant-cointegrated series for each country. They were tested by the augmented Dickey-Fuller test for stationarity to confirm a constant long-term stochastic intervariant interaction within the country.

Results

The trend series of seasonality-adjusted global COVID-19 new cases was found to be heteroscedastic (p = 0.002), while its rate of change was indeterministic (p = 0.052) and stationary (p = 0.024). Seasonal cointegration relationships between expected new case series by variants were found in 37 out of 48 countries (p < 0.05), reflecting a constant long-term stochastic trend in new case numbers contributed from different variants of concern within most countries.

Conclusion

Our results indicated that the new case long-term trends were random on a global scale and stable within most countries; therefore, the virus was unlikely to be eliminated but containable. Policymakers are currently in the process of adapting to the transformation of the pandemic into an endemic.

COVID-19 Vaccination in China: Adverse Effects and Its Impact on Health Care Working Decisions on Booster Dose

Although many research studies have concentrated on people’s willingness to take the COVID-19 vaccine, little attention has been paid to the underlying mechanism of consent. An understanding of potential factors and mechanisms that affect the willingness to receive a vaccination can contribute information critical for containing the pandemic. This study explored the effects of post-vaccination adverse reactions on the willingness to take the booster dose and the role of decision regret. A self-administered online survey was carried out in Taizhou, China. Questionnaires were completed by 1085 healthcare workers (HCWs), 1054 (97.1%) of whom had completed two doses of the COVID-19 vaccine. Mediation analysis methodology was applied in this study. Our study showed that post-vaccination adverse reactions in HCWs could decrease their willingness to take the booster dose. Of note, HCWs who experienced adverse reactions after vaccination would be more likely to regret their previous vaccination decisions, which, in turn, further reduced their willingness to receive a booster shot. Decision regret mediated the relationship between adverse post-vaccination reactions and a willingness to take the booster dose. The findings implied inextricable relationships among post-vaccination adverse reactions, decision regret, and willingness to take the booster dose. It is suggested that notice of these post-vaccination adverse reactions should be further incorporated into vaccine communication campaigns and policy interventions advocating booster doses to improve vaccine uptake intent and increase the willingness to receive booster doses of a COVID-19 vaccine.