COVID-19 vaccination in the mass vaccination center: clinical practice and effectiveness analysis

Abstract

ObjectivesMass vaccination campaigns can rapidly increase the vaccination rate for the COVID-19 vaccine, the establishment of mass vaccination centers is indispensable. At the beginning of March 2021, China began to carry out COVID-19 vaccination activities nationwide. Here, we aimed to evaluate the criteria established by mass vaccination centers, COVID-19 vaccination experience, the incidence of adverse events following immunization and opinions.MethodsWe describe the layout and functioning of Nan’an District mass vaccination center, the working mechanism, experience and effectiveness. Distribution of COVID-19 vaccine vaccination and adverse events following immunization reported in the mass vaccination center of Nan’an District were evaluated.ResultsFrom March 26, 2021 to April 28, 2022, the mass vaccination center has inoculated about 381,364 doses of COVID-19 vaccine to the population. The study found that the incidence of adverse events following immunization (AEFI) was very low (1.04/100000). The chances of having AEFI were significantly higher in COVID-19 vaccine (CHO cell) than COVID-19 vaccine (Vero cell).ConclusionThe mass vaccination center was running successfully. It was effective and safe, providing vaccination services and increasing COVID-19 vaccination rates among the population. The experience of the mass vaccination center for COVID-19 in China can provide a reference for other countries and regions to carry out COVID-19 vaccination.

Effect of the mass vaccination duration on the spread of COVID-19 evaluated by a flexible compartment model

“…Since RP(n) is the number of infected individuals minus the number of isolated individuals (PI(n)), of the dead (DAS(n)) and of the recovered individuals living in the community (RAS(n)) from the total number of infected individuals up to date n, it is given by the following equation: RP(n)=Σ(AP(n)-PI(n-1)-DAS(n-1)-RAS(n)) (9) where PI (n) is the number of symptomatic individuals who become symptomatic on the day after the end of the latent period in the real community and are isolated on the next day. PI(n) is given by: PI(n) = AP(n-(lp + 1))* syr(n-(lp + 1)) (10) where lp(n) is the latent period, and (n-(lp + 1)) indicates the 'latent period + 1' before date n, meaning the day after the end of the latent period, because the infected individuals become symptomatic and are isolated on the day after the end of the latent period, as explained in 4 − 3 'Symptomatic rate'. The value of AP(n-(lp + 1)) is the number of infected individuals who were newly infected on date (n-(lp + 1)), which is the day after the end of the latent period.…”

“…From a viewpoint of herd immunity to contain the COVID-19 pandemic, however, the mass vaccination duration, which is not the vaccination interval, for example, a period between the primary vaccination and the booster dose, but here the period between the start and the end of mass vaccination, must need to be examined because the total number of vaccinated individuals, which practically controls the spread of COVID-19, practically depends on the mass vaccination duration. Namely, the total number of vaccinated individuals is practically decided by the mass vaccination duration because the number of vaccinated individuals actually increases gradually day by day even for a successful vaccination process as there is a limit of the number of individuals vaccinated a day for any community due to the limit of the supply of vaccines and vaccinators (staff and equipment) and, as noted by Fan et al (2023) [10], practically due to the staff turnover in mass vaccination center and others.…”

Effect of the mass vaccination duration on the spread of COVID-19 evaluated by a flexible compartment model

“…From the viewpoint of herd immunity to contain the COVID-19 pandemic, however, the mass vaccination duration, which is not the vaccination interval, for example, the period between the primary vaccination and the booster dose but rather the period between the start and the end of mass vaccination, must be examined because the total number of vaccinated individuals, which practically controls the spread of COVID-19, depends on the mass vaccination duration. Namely, the total number of vaccinated individuals is practically decided by the mass vaccination duration because the number of vaccinated individuals actually increases gradually day by day even for a successful vaccination process, as there is a limit on the number of individuals vaccinated a day for any community due to the limit of the supply of vaccines and vaccinators (staff and equipment) and, as noted by Fan et al (2023) [10], practically due to staff turnover in mass vaccination centers and others.…”

Effect of the mass vaccination duration on the spread of COVID-19 evaluated by a flexible compartment model

“…From the viewpoint of herd immunity to contain the COVID-19 pandemic, however, the mass vaccination duration, which is not the vaccination interval, for example, a period between the primary vaccination and the booster dose, but here, the period between the start and the end of mass vaccination, must be examined because the total number of vaccinated individuals, which practically controls the spread of COVID-19, depends on the mass vaccination duration. Namely, the total number of vaccinated individuals is practically decided by the mass vaccination duration because the number of vaccinated individuals actually increases gradually day by day even for a successful vaccination process, as there is a limit of the number of individuals vaccinated a day for any community due to the limit of the supply of vaccines and vaccinators (staff and equipment) and, as noted by Fan et al (2023) [10], practically due to the staff turnover in mass vaccination centers and others.…”