mRNA vaccine effectiveness against COVID-19-related hospitalisations and deaths in older adults: a cohort study based on data linkage of national health registries in Portugal, February to August 2021

Nunes, Baltazar; Rodrigues, Ana Paula; Kislaya, Irina; Cruz, Camila; Peralta‐Santos, André; Lima, João; Leite, Pedro Pinto; Sequeira, Duarte João; Dias, Carlos Matias; Machado, Ausenda

doi:10.2807/1560-7917.es.2021.26.38.2100833

Cited by 53 publications

(67 citation statements)

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“…After completed vaccination schemes, we observed a decay of the VE estimates with time, particularly against symptomatic infection and in the 80 and more yo cohort, where VE decay was observed for both symptomatic infection and hospitalizations. The drop over time of VE against symptomatic infection has also been reported by several authors [14][15][16] but the decay of VE against hospitalization had not yet observed as far as we know [14][15][16][17]. In part, this result may be explained by an insufficient time of follow up.…”

Section: Key Resultsmentioning

confidence: 62%

“…Vaccine effectiveness (VE) against COVID-19 related hospital admissions and mortality in older adults populations varied between 94-97% for the completed vaccination scheme in December 2020 -April 2021 [10][11][12][13]. Following the emergence of the Delta SARS-CoV-2 VOC, studies showed a decrease in VE for both mRNA and AstraZeneca vaccines for symptomatic infections in the general population [14][15][16], but sustained VE estimates against hospitalizations [14][15][16][17] and COVID-19-related mortality [15].…”

Section: Introductionmentioning

confidence: 99%

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COVID-19 vaccine effectiveness against laboratory confirmed symptomatic SARS-CoV-2 infection, COVID-19 related hospitalizations and deaths, among individuals aged 65 years or more in Portugal: a cohort study based on data-linkage of national registries February-September 2021

Machado

Kislaya

Rodrigues

et al. 2021

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BackgroundUsing data from electronic health registries, this study intended to estimate the COVID-19 vaccine effectiveness in the population aged 65 years and more, against symptomatic infection, COVID-19 related hospitalizations and deaths, overall and by time since complete vaccination.MethodsWe stablished a cohort of individuals aged 65 and more years old, resident in Portugal mainland, using the National Health Service unique identifier User number to link eight electronic health registries. Outcomes included were symptomatic SARS-CoV-2 infections, COVID-19 related hospitalizations or deaths. The exposures of interest were the mRNA vaccines (Cominarty or Spikevax) and the viral vector Vaxzevria vaccine. Complete scheme vaccine effectiveness (VE) was estimated as one minus the confounder adjusted hazard ratio, for each outcome, estimated by time-dependent Cox regression with time dependent vaccine exposure.ResultsFor the cohort of individuals aged 65-79 years, complete scheme VE against symptomatic infection varied between 43% (Vaxzevria) and 65% (mRNA vaccines). This estimate was slightly lower in the ≥80 year cohort (53% for mRNA vaccines. VE against COVID-19 hospitalization varied between 89% (95%CI: 52-94) for Vaxzevria and 95% (95%CI: 93-97) for mRNA vaccines for the cohort aged 65-79 years and was 76% (95%CI: 67-83) for mRNA vaccines in the ≥80 year cohort. High VE against COVID-19 related deaths were estimated, for both vaccine types, 95% and 81% for the 65-79 years and the ≥80 year cohort, respectively.We observed a significant waning of VE against symptomatic infection, with VE estimates reaching approximately 34% for both vaccine types and cohorts. Significant waning was observed for the COVID-19 hospitalizations in the ≥80 year cohort (decay from 83% 14-41 days to 63% 124 days after mRNA second dose). No significant waning effect was observed for COVID-19 related deaths in the period of follow-up of either cohorts.ConclusionsIn a population with a high risk of SARS-CoV-2 complications, we observed higher overall VE estimates against more severe outcomes for both age cohorts when compared to symptomatic infections. Considering the analysis of VE according to time since complete vaccination, the results showed a waning effect for both age cohorts in symptomatic infection and COVID-19 hospitalization for the 80 and more yo cohort.

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Section: Key Resultsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

COVID-19 vaccine effectiveness against laboratory confirmed symptomatic SARS-CoV-2 infection, COVID-19 related hospitalizations and deaths, among individuals aged 65 years or more in Portugal: a cohort study based on data-linkage of national registries February-September 2021

Machado

Kislaya

Rodrigues

et al. 2021

Preprint

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“…The elderly population is greatly affected by COVID-19, mainly due to the age-related changes affecting immune responses [ 29 ]. Vaccination has been proven essential for the reduction in the severity and mortality of older subjects [ 30 , 31 ], but it is known that age-related immune response defects provoke a lower level of protection after vaccination compared to younger subjects [ 11 , 12 , 13 ]. In this sense, several authors have highlighted the importance of using probiotic supplementation as adjuvants for boosting immunity and enhancing vaccine-specific responses in the elderly population [ 24 , 25 ].…”

Section: Discussionmentioning

confidence: 99%

Effects of Loigolactobacillus coryniformis K8 CECT 5711 on the Immune Response of Elderly Subjects to COVID-19 Vaccination: A Randomized Controlled Trial

et al. 2022

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Elderly people are particularly vulnerable to COVID-19, with a high risk of developing severe disease and a reduced immune response to the COVID-19 vaccine. A randomized, placebo-controlled, double-blind trial to assess the effect of the consumption of the probiotic Loigolactobacillus coryniformis K8 CECT 5711 on the immune response generated by the COVID-19 vaccine in an elderly population was performed. Two hundred nursing home residents >60 yrs that had not COVID-19 were randomized to receive L. coryniformis K8 or a placebo daily for 3 months. All volunteers received a complete vaccination schedule of a mRNA vaccine, starting the intervention ten days after the first dose. Specific IgG and IgA antibody levels were analyzed 56 days after the end of the immunization process. No differences between the groups were observed in the antibody levels. During the intervention, 19 subjects had COVID-19 (11 receiving K8 vs. 8 receiving placebo, p = 0.457). Subgroup analysis in these patients showed that levels of IgG were significantly higher in those receiving K8 compared to placebo (p = 0.038). Among subjects >85 yrs that did not get COVID-19, administration of K8 tended to increase the IgA levels (p = 0.082). The administration of K8 may enhance the specific immune response against COVID-19 and may improve the COVID-19 vaccine-specific responses in elderly populations.

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“…In the same way, two-dose reg-imen generated high sera-neutralization levels against the Alpha, Beta and Delta variants in individuals sampled at week 8 to week 16 after vaccination [26], being the levels of neutralizing antibodies highly predictive of immune protection from symptomatic SARS-CoV-2 infection [27]. A study at national level estimated high mRNA VE for the prevention of COVID-19-related hospitalizations and deaths (in ≥ 65 years, full vaccinated) with any evidence of VE reduction in the 3 months after the second dose uptake, during the period of Delta variant circulation [28], consistent with the high titers for binding and neutralizing antibodies detected after complete vaccination.…”

Section: Discussionmentioning

confidence: 99%

High correlation between binding IgG (anti-RBD/S) and neutralizing antibodies against SARS-CoV-2 six months after vaccination

Guiomar

Santos

Melo

et al. 2021

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Vaccination is considered the most important measure to control the COVID-19 pandemic. Extensive follow-up studies with distinct vaccines and populations are able to promote robust and reliable data to better understand the effectiveness of this pharmacologic strategy. In this sense, we present data regarding binding and neutralizing antibodies throughout time, from vaccinated and previously infected (PI) health care workers (HCW) in Portugal. We analyzed serum samples of 132 HCW, vaccinated and with previous SARS-CoV-2 infection. Samples were collected before vaccination (baseline, M1), at second dose vaccine uptake (M2), and 25-70 days (M3) and 150-210 days (M4) after the second dose for vaccinated individuals. The IgG (anti-RBD/S) antibody geometric mean titer found on vaccinated HCW at M2 (814.7 AU/ml; 95% CI 649.8-1021.5) were significantly higher than those found on PI HCW at recruitment (M1) (252.6 AU/ml; 95% CI 108.7 - 587.1), and the neutralizing antibodies (nAb) were similar between these groups, 93.2 UI/ml (95% CI 73.2-118.5) vs. 84.1 UI/ml (95% CI 40.4-155.9), respectively. We detected about 10-fold higher IgG (anti-RBD/S) antibodies titers in M3 when compared with M2, with a slightly but significant decrease in titers from 36 days after the second dose vaccine uptake. The increase of nAb titers were correlated with IgG (anti-RBD/S) antibodies titers, however, contrasting to IgG (anti-RBD/S) antibodies titers, we did not detect a decrease in nAb titer from 36 days after a second vaccine dose uptake. At M4, was observed a decrease of 8-fold in binding IgG (anti-RBD/S) and nAb. No significant differences in antibody titers were observed by sex, age or chronic diseases. Our results suggest that IgG (anti-RBD/S) antibodies titers and nAb titers could be correlated, but ongoing follow up of the cohort, is required to better understand this correlation, and the duration of the immune response.

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mRNA vaccine effectiveness against COVID-19-related hospitalisations and deaths in older adults: a cohort study based on data linkage of national health registries in Portugal, February to August 2021

Cited by 53 publications

References 6 publications

COVID-19 vaccine effectiveness against laboratory confirmed symptomatic SARS-CoV-2 infection, COVID-19 related hospitalizations and deaths, among individuals aged 65 years or more in Portugal: a cohort study based on data-linkage of national registries February-September 2021

COVID-19 vaccine effectiveness against laboratory confirmed symptomatic SARS-CoV-2 infection, COVID-19 related hospitalizations and deaths, among individuals aged 65 years or more in Portugal: a cohort study based on data-linkage of national registries February-September 2021

Effects of Loigolactobacillus coryniformis K8 CECT 5711 on the Immune Response of Elderly Subjects to COVID-19 Vaccination: A Randomized Controlled Trial

High correlation between binding IgG (anti-RBD/S) and neutralizing antibodies against SARS-CoV-2 six months after vaccination

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