Why promoting a COVID-19 vaccine booster dose?

Loubet, Paul; Laureillard, Didier; Martin, Aurélie; Larcher, Romaric; Sotto, Albert

doi:10.1016/j.accpm.2021.100967

Cited by 22 publications

(19 citation statements)

References 8 publications

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“…However, neutralizing antibodies that can intercept viruses before they penetrate cells do not have much staying power, while cellular immune responses are longer-lasting [ 47 ]. Therefore, a booster dose is a “trigger” that can stimulate B cells to secrete more neutralizing antibodies, so as to prevent the invasion of SARS-CoV-2 [ 49 ]. The results of this meta-analysis confirmed the benefit of booster vaccinations, and it also indicated that the immunogenicity of heterologous immunization was much better.…”

Section: Discussionmentioning

confidence: 99%

Immunogenicity and Safety of Homologous and Heterologous Prime–Boost Immunization with COVID-19 Vaccine: Systematic Review and Meta-Analysis

Cheng

Peng

et al. 2022

Vaccines

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A prime–boost strategy of COVID-19 vaccines brings hope to limit the spread of SARS-CoV-2, while the immunogenicity of the vaccines is waning over time. Whether a booster dose of vaccine is needed has become a widely controversial issue. However, no published meta-analysis has focused on the issue. Therefore, this study assessed the immunogenicity and safety of the different combinations of prime–boost vaccinations. Electronic databases including PubMed, the Cochrane Library, Embase, medRxiv, Wanfang and CNKI were used to retrieve the original studies. A total of 28 studies, 9 combinations of prime–boost vaccinations and 5870 subjects were included in the meta-analysis, and random effect models were used to estimate pooled immunogenicity and safety. The immunity against COVID-19 after the prime vaccination waned over time, especially in the populations primed with inactivated vaccines, in which the seropositive rate of antibodies was only 28% (95% CI: 17–40%). Booster vaccination could significantly increase the antibody responses, and heterologous immunization was more effective than homologous immunization (neutralization titers: 1.65 vs. 1.27; anti-RBD IgG: 1.85 vs. 1.15); in particular, the combination of inactivated–mRNA vaccines had the highest antibody responses (neutralization titers: MRAW = 3.64, 95% CI: 3.54–3.74; anti-RBD IgG: 3.73, 95% CI: 3.59–3.87). Moreover, compared with the initial two doses of vaccines, a booster dose did not induce additional or severe adverse events. The administration of the booster dose effectively recalled specific immune responses to SARS-CoV-2 and increased antibody levels, especially in heterologous immunization. Considering the long-term immunogenicity and vaccine equity, we suggest that now, only individuals primed with inactivated vaccines require a booster dose.

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Section: Discussionmentioning

confidence: 99%

Immunogenicity and Safety of Homologous and Heterologous Prime–Boost Immunization with COVID-19 Vaccine: Systematic Review and Meta-Analysis

Cheng

Peng

et al. 2022

Vaccines

View full text Add to dashboard Cite

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“…Although the COVID-19 vaccine has been shown to induce a robust immune response toward the virus, its duration is still inconclusive. 97 However, studies have reported that waning of neutralizing antibody levels occurs 6 months post-vaccination. 98,99 With so many unknowns about the virus and its continuous mutations, it is plausible that several booster shots will be required.…”

Section: Discussionmentioning

confidence: 99%

A Mapping Review on the Uptake of the COVID-19 Vaccine among Adults in Africa Using the 5As Vaccine Taxonomy

Kalu

Oyinlola

Ibekaku

et al. 2022

The American Journal of Tropical Medicine and Hygiene

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Uptake of a vaccine is complete if individuals are aware of the associated risks of the vaccine, accept the vaccine, and respond positively to the nudges (activation) to increase the uptake, and respond when the vaccine is made accessible and affordable. We mapped systematically the existing literature concerning the 5As—acceptability, accessibility, affordability, awareness, and activation—of COVID-19 vaccination among adults and, specifically, older adults (55 years and older) in Africa. We searched multiple databases from 2020 to December 2021. Using predefined inclusion and exclusion criteria, two reviewers screened citations, conducted title and abstract screening, and extracted data independently. We included 68 articles conducted in 33 African countries, primarily cross-sectional studies (n = 49, 72%). None of the articles focused on older adults only, but 22 articles (32%) included at least one older adult (55 years and older) in their sample size. Acceptance (n = 58, 85%) was the most commonly researched aspect of vaccine uptake, followed by accessibility (n = 17, 25%), awareness (n = 13, 19%), and affordability (n = 5, 7.0%). We found only one report on activation. Factors affecting acceptance of the COVID-19 vaccine in Africa were grouped into sociodemographic factors; knowledge-, attitude-, and belief-related factors; a COVID-19 vaccine efficacy and safety concern factor; and trust in government and public health authorities. The governments of African nations should focus on strategies to influence the modifiable factors identified in this review. More studies are needed to evaluate the impact of nudges (activation) to improve COVID-19 vaccine uptake in African nations.

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“…Considering the potential waning of immunity from the standard two-dose regimens and the emerging variants of concern, many governments are now initiating the administration of a third dose (or booster) as an attempt to maintain immune protection in the population, especially for the elderly and immunocompromised individuals who are more at risk of severe COVID-19 [ 57 , 58 ]. Both randomized and observational studies have recently demonstrated that the third dose could significantly enhance the neutralizing antibody responses that have been waning over time among individuals fully vaccinated with two doses, which in turn protect them against SARS-CoV-2 infection, severe COVID-19, and related death, and possibly reducing transmission in the community; these have been observed with both BNT162b2 [ 59 – 63 ] and CoronaVac [ 6 , 58 , 64 , 65 ], notably in extended dosing intervals and heterologous vaccination.…”

Section: Discussionmentioning

confidence: 99%

Impact of a delayed second dose of mRNA vaccine (BNT162b2) and inactivated SARS-CoV-2 vaccine (CoronaVac) on risks of all-cause mortality, emergency department visit, and unscheduled hospitalization

Wong

Xiong

Lau

et al. 2022

BMC Med

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Background Safety after the second dose of the SARS-CoV-2 vaccine remains to be elucidated, especially among individuals reporting adverse events after their first dose. This study aims to evaluate the impact of a delayed second dose on all-cause mortality and emergency services. Methods A territory-wide, retrospective cohort of people who had completed two doses of mRNA (BNT162b2) or inactivated SARS-CoV-2 (CoronaVac) vaccine between February 23 and July 3, 2021, in Hong Kong was analyzed, with linkage to electronic health records retrieved from the Hong Kong Hospital Authority. Vaccine recipients were classified as receiving a second dose within recommended intervals (21–28 days for BNT162b2; 14–28 days for CoronaVac) or delayed. Study outcomes were all-cause mortality, emergency department (ED) visits, and unscheduled hospitalizations within 28 days after the second dose of vaccination. Results Among 417,497 BNT162b2 and 354,283 CoronaVac second dose recipients, 3.8% and 28.5% received the second dose beyond the recommended intervals (mean 34.4 and 31.8 days), respectively. During the study period, there were < 5 daily new cases of COVID-19 infections in the community. Delaying the second dose was not associated with all-cause mortality (hazard ratio [HR] = 1.185, 95% CI 0.478–2.937, P = 0.714), risk of ED visit (HR = 0.966, 95% CI 0.926–1.008, P = 0.113), and risk of unscheduled hospitalization (HR = 0.956, 95% CI 0.878–1.040, P = 0.294) compared to that within the recommended interval for CoronaVac recipients. No statistically significant differences in all-cause mortality (HR = 4.438, 95% CI 0.951–20.701, P = 0.058), ED visit (HR = 1.037, 95% CI 0.951–1.130, P = 0.411), and unscheduled hospitalization (HR = 1.054, 95% CI 0.867–1.281, P = 0.597) were identified between people who received a second dose of BNT162b2 within and beyond the recommended intervals. Conclusions No significant association between delayed second dose of BNT162b2 or CoronaVac and all-cause mortality, ED visit, and unscheduled hospitalization was observed in the present cohort. Regardless of the recommended or delayed schedule for SARS-CoV-2 vaccination, a second dose of both vaccines should be administered to obtain better protection against infection and serious disease. The second dose should be administered within the recommended interval following the manufacturer’s product information, until further studies support the benefits of delaying vaccination outweighing the risks.

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Why promoting a COVID-19 vaccine booster dose?

Cited by 22 publications

References 8 publications

Immunogenicity and Safety of Homologous and Heterologous Prime–Boost Immunization with COVID-19 Vaccine: Systematic Review and Meta-Analysis

Immunogenicity and Safety of Homologous and Heterologous Prime–Boost Immunization with COVID-19 Vaccine: Systematic Review and Meta-Analysis

A Mapping Review on the Uptake of the COVID-19 Vaccine among Adults in Africa Using the 5As Vaccine Taxonomy

Impact of a delayed second dose of mRNA vaccine (BNT162b2) and inactivated SARS-CoV-2 vaccine (CoronaVac) on risks of all-cause mortality, emergency department visit, and unscheduled hospitalization

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