Effectiveness of COVID-19 Vaccines among Incarcerated People in California State Prisons: A Retrospective Cohort Study

Attitudes towards COVID-19 vaccination among incarcerated persons in the Federal Bureau of Prisons, June-July 2021

OBJECTIVE

To understand the attitudes towards COVID-19 vaccination and trusted sources of vaccination-related information among persons incarcerated in the Federal Bureau of Prisons.

METHODS

From June-July 2021, persons incarcerated across 122 facilities operated by the Federal Bureau of Prisons were invited to participate in a survey asking their reasons for receiving or declining COVID-19 vaccination and the information sources they relied upon to make these decisions. Descriptive analyses were conducted.

RESULTS

A total of 130,789 incarcerated persons with known vaccination status were invited to participate in the survey. At the time of survey, 78,496 (62%) were fully vaccinated; 3,128 (3%) were partially vaccinated and scheduled to complete their second dose, and 44,394 (35%) had declined either a first or second dose. 7,474 (9.5%) of the fully vaccinated group and 2,302 (4.4%) of the group declining either a first or second dose chose to participate in the survey; an overall survey return rate of 7.6% (n = 9,905). Among vaccinated respondents, the most common reason given for accepting vaccination was to protect their health (n = 5,689; 76.1%). Individuals who declined vaccination cited concerns about vaccine side effects (n = 1,304; 56.6%), mistrust of the vaccine (n = 1,256; 54.6%), and vaccine safety concerns (n = 1,252; 54.4%). Among those who declined, 21.2% (n = 489) reported that they would choose to be vaccinated if the vaccine was offered again. Those who declined also reported that additional information from outside organizations (n = 1128; 49.0%), receiving information regarding vaccine safety (n = 841; 36.5%), and/or speaking with a trusted medical advisor (n = 565; 24.5%) may influence their decision to be vaccinated in the future.

CONCLUSION

As the COVID-19 pandemic continues, it is important to increase vaccine confidence in prisons, jails, and detention facilities to reduce transmission and severe health outcomes. These survey findings can inform the design of potential interventions to increase COVID-19 vaccine uptake in these settings.

Effectiveness of heterologous and homologous covid-19 vaccine regimens: living systematic review with network meta-analysis

OBJECTIVE

To evaluate the effectiveness of heterologous and homologous covid-19 vaccine regimens with and without boosting in preventing covid-19 related infection, hospital admission, and death.

DESIGN

Living systematic review and network meta-analysis.

DATA SOURCES

World Health Organization covid-19 databases, including 38 sources of published studies and preprints.

STUDY SELECTION

Randomised controlled trials, cohort studies, and case-control studies.

METHODS

38 WHO covid-19 databases were searched on a weekly basis from 8 March 2022 to 31 July 2022. Studies that assessed the effectiveness of heterologous and homologous covid-19 vaccine regimens with or without a booster were identified. Studies were eligible when they reported the number of documented, symptomatic, severe covid-19 infections, covid-19 related hospital admissions, or covid-19 related deaths among populations that were vaccinated and unvaccinated. The primary measure was vaccine effectiveness calculated as 1−odds ratio. Secondary measures were surface under the cumulative ranking curve (SUCRA) scores and the relative effects for pairwise comparisons. The risk of bias was evaluated by using the risk of bias in non-randomised studies of interventions (ROBINS-I) tool for all cohort and case-control studies. The Cochrane risk of bias tool (version 2; ROB-2) was used to assess randomised controlled trials.

RESULTS

The second iteration of the analysis comprised 63 studies. 25 combinations of covid-19 vaccine regimens were identified, of which three doses of mRNA vaccine were found to be 93% (95% credible interval 70% to 98%) effective against asymptomatic or symptomatic covid-19 infections for non-delta or non-omicron related infections. Heterologous boosting using two dose adenovirus vector vaccines with one dose mRNA vaccine showed a vaccine effectiveness of 94% (72% to 99%) against non-delta or non-omicron related asymptomatic or symptomatic infections. Three doses of mRNA vaccine were found to be the most effective in reducing non-delta or non-omicron related hospital admission (96%, 82% to 99%). The vaccine effectiveness against death in people who received three doses of mRNA vaccine remains uncertain owing to confounders. The estimate for a four dose mRNA vaccine regimen was of low certainty, as only one study on the effectiveness of four doses could be included in this update. More evidence on four dose regimens will be needed to accurately assess the effectiveness of a fourth vaccine dose. For people with delta or omicron related infection, a two dose regimen of an adenovirus vector vaccine with one dose of mRNA booster was 77% (42% to 91%) effective against asymptomatic or symptomatic covid-19 infections, and a three dose regimen of a mRNA vaccine was 93% (76% to 98%) effective against covid-19 related hospital admission.

CONCLUSION

An mRNA booster is recommended to supplement any primary vaccine course. Heterologous and homologous three dose regimens work comparably well in preventing covid-19 infections, even against different variants. The effectiveness of three dose vaccine regimens against covid-19 related death remains uncertain.

SYSTEMATIC REVIEW REGISTRATION

This review was not registered. The protocol is included in the supplementary document.

READERS' NOTE

This article is a living systematic review that will be updated to reflect emerging evidence. Updates may occur for up to two years from the date of original publication. This version is update 1 of the original article published on 31 May 2022 (BMJ 2022;377:e069989), and previous versions can be found as data supplements (https://www.bmj.com/content/377/bmj-2022-069989/related). When citing this paper please consider adding the version number and date of access for clarity.

Protection against Omicron conferred by mRNA primary vaccine series, boosters, and prior infection

B ackground

Prisons and jails are high-risk settings for Covid-19 transmission, morbidity, and mortality. We evaluate protection conferred by prior infection and vaccination against the SARS-CoV-2 Omicron variant within the California state prison system.

M ethods

We employed a test-negative design to match resident and staff cases during the Omicron wave (December 24, 2021-April 14, 2022) to controls according to a case's test-week as well as demographic, clinical, and carceral characteristics. We estimated protection against infection using conditional logistic regression, with exposure status defined by vaccination, stratified by number of mRNA doses received, and prior infection, stratified by periods before or during Delta variant predominance.

R esults

We matched 15,783 resident and 8,539 staff cases to 180,169 resident and 90,409 staff controls. Among cases, 29.7% and 2.2% were infected before or during the emergence of the Delta variant, respectively; 30.6% and 36.3% were vaccinated with two or three doses, respectively. Estimated protection from Omicron infection for two and three doses were 14.9% (95% Confidence Interval [CI], 12.3-19.7%) and 43.2% (42.2-47.4%) for those without known prior infections, 47.8% (95% CI, 46.6-52.8%) and 61.3% (95% CI, 60.7-64.8%) for those infected before the emergence of Delta, and 73.1% (95% CI, 69.8-80.1%) and 86.8% (95% CI, 82.1-92.7) for those infected during the period of Delta predominance.

C onclusion

A third mRNA dose provided significant, additional protection over two doses, including among individuals with prior infection. Our findings suggest that vaccination should remain a priority-even in settings with high levels of transmission and prior infection.