Implementing vaccination policies based upon scientific evidence in Japan

Effect of vaccination patterns and vaccination rates on the spread and mortality of the COVID-19 pandemic

Objectives

Acquiring herd immunity through vaccination is the best way to curb the COVID-19 infection. Many countries have attempted to reach the herd immunity threshold as early as possible since the commencement of vaccination at the end of 2020. The purpose of this study is to (1) examine whether the pattern of vaccination rates affects the spread of COVID-19 and the consequent mortality and (2) investigate the level of cumulative vaccination rates that can begin to have an impact on reducing the spread and mortality of the pandemic.

Methods

This study selected 33 countries with higher vaccination rates as its sample set, classifying them into three groups as per vaccination patterns.

Results

The results showed that vaccination patterns have a significant impact on reducing spread and mortality. The full-speed vaccination pattern showed greater improvement in the spread of the COVID-19 pandemic than the other two patterns, while the striving vaccination pattern improved the most in terms of mortality. Secondly, the spread and mortality of the COVID pandemic started to significantly decline when the average cumulative vaccination rate reached 29.06 doses per 100 people and 7.88 doses per 100 people, respectively.

Conclusion

The study highlights the important role of vaccination patterns and the VTMR in reducing the epidemic spread and mortality.

COVID-19 pandemic over 2020 (withlockdowns) and 2021 (with vaccinations): similar effects for seasonality and environmental factors

How is the dynamics of Coronavirus Disease 2019 (COVID-19) in 2020 with an health policy of full lockdowns and in 2021 with a vast campaign of vaccinations? The present study confronts this question here by developing a comparative analysis of the effects of COVID-19 pandemic between April-September 2020 (based upon strong control measures) and April-September 2021 (focused on health policy of vaccinations) in Italy, which was one of the first European countries to experience in 2020 high numbers of COVID-19 related infected individuals and deaths and in 2021 Italy has a high share of people fully vaccinated against COVID-19 (>89% of population aged over 12 years in January 2022). Results suggest that over the period under study, the arithmetic mean of confirmed cases, hospitalizations of people and admissions to Intensive Care Units (ICUs) in 2020 and 2021 is significantly equal (p-value<0.01), except fatality rate. Results suggest in December 2021 lower hospitalizations, admissions to ICUs, and fatality rate of COVID-19 than December 2020, though confirmed cases and mortality rates are in 2021 higher than 2020, and likely converging trends in the first quarter of 2022. These findings reveal that COVID-19 pandemic is driven by seasonality and environmental factors that reduce the negative effects in summer period, regardless control measures and/or vaccination campaigns. These findings here can be of benefit to design health policy responses of crisis management considering the growth of COVID-19 pandemic in winter months having reduced temperatures and low solar radiations ( COVID-19 has a behaviour of influenza-like illness). Hence, findings here suggest that strategies of prevention and control of infectious diseases similar to COVID-19 should be set up in summer months and fully implemented during low-solar-irradiation periods (autumn and winter period).

Comparison of Side Effects of COVID-19 Vaccines: Sinopharm, AstraZeneca, Sputnik V, and Covaxin in Women in Terms of Menstruation Disturbances, Hirsutism, and Metrorrhagia: A Descriptive-Analytical Cross-Sectional Study

BACKGROUND

Present study assessed whether Sinopharm, AstraZeneca, Sputnik V, and Covaxin's vaccinated women<br />reveal a distinct incidence of menstruation disturbances, hirsutism, and metrorrhagia.<br />Materials and Methods: Data collection was performed from June to August 2021, and 427 women working in seven<br />selected hospitals in Tehran were studied in this descriptive-analytical cross-sectional study. All of these women had<br />received one or both doses of the vaccines with one of the assessed vaccines. Required data was collected via questionnaire<br />and imported to SPSS 16 for further assessment and analysis. Fisher's Exact Test and Chi-Squared test were<br />main statistical tests used to understand whether any significant relation exists or not.<br />Results: The participant's mean age and body mass index (BMI) were 29.78 ± 10.55 and 23.27 ± 3.82, respectively.<br />Three hundred ninety-five cases (92.4%) had received both doses of the vaccines. Also, 154 cases (36.1%) had a history<br />of COVID-19. A total of 38 cases (8.8%) of menstruation disturbances, 20 cases (4.6%) of metrorrhagia, and 7<br />cases (1.6%) of hirsutism were reported after receiving the vaccines. There was a significant difference among the<br />vaccinated groups with the vaccines as mentioned earlier in terms of menstruation disturbances (hypermenorrhea,<br />dysmenorrhea, Amenorrhea) (P=0.01). The highest and the lowest incidence of menstruation disturbances were recorded<br />in the group vaccinated with Covaxin (17.6%) and Sputnik V (5%), respectively. There was also no significant<br />difference amongst the vaccinated groups with the four vaccines regarding the incidence of metrorrhagia and<br />hirsutism (P=0.10 and P=0.12, respectively). There was no significant relationship between all three complications<br />incidence with the previous infection concerning all vaccines (coefficient=0.46, 1.27, -0.15 respectively for menstruation<br />disturbances, metrorrhagia, and, hirsutism).<br />Conclusion: Seemingly, Covaxin revealed the most side effects in terms of menstruation disturbances. As a result, professionals<br />must carry out several studies with reasonable samples to recommend the vaccine to those women confidently.