Evidence map›Paper›PMID 40620571›Full record

ArticleBMJ public health2025

Antispike IgG antibody decay after immunisation with fractional versus full booster doses of COVID-19 vaccines: a 6-month longitudinal analysis of the FRACT-COV trial in Brazil.

Juliana Barros Verruck, Marco Antonio Moreira Puga, Roberto Dias de Oliveira, Patricia Vieira da Silva, Vivek Charu, Haley Hedlin, Di Lu, Amy Zhang, Victor Ritter, Blake Shaw and 7 more

Registry-linked trialAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in BMJ public health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05343871 (Randomized Controlled Trial to Assess the Immunogenicity and Safety of Full Versus Fractional Dose of Pfizer/BioNTech, AstraZeneca, and Sinovac COVID-19 Vaccines Given as a Booster Dose at Least 6 Months After Primary Vaccination Series or PCR-confirmed Infection With SARS-CoV-2 in Healthy Adults), which is not on this map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05343871 phase4completednot on this map

Randomized Controlled Trial to Assess the Immunogenicity and Safety of Full Versus Fractional Dose of Pfizer/BioNTech, AstraZeneca, and Sinovac COVID-19 Vaccines Given as a Booster Dose at Least 6 Months After Primary Vaccination Series or PCR-confirmed Infection With SARS-CoV-2 in Healthy Adults

TypeinterventionalSponsorAlbert B. Sabin Vaccine InstituteRan2022 to 2024Enrolled2,354ConditionsCOVID-19ArmsSinovac, AZD1222, BNT162b2
3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Trial
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

17 authors.

Juliana Barros Verruck *University of California Berkeley School of Public Health, Berkeley, California, USA.ORCID https://orcid.org/0009-0001-1673-8486
Marco Antonio Moreira Puga *Fundação Oswaldo Cruz, Fiocruz Mato Grosso do Sul, Campo Grande, Brazil.ORCID https://orcid.org/0000-0002-6514-537X
Roberto Dias de OliveiraNursing Course, Universidade Estadual do Mato Grosso do Sul, Dourados, Brazil.ORCID https://orcid.org/0000-0001-7996-8011
Patricia Vieira da SilvaFundação Oswaldo Cruz, Fiocruz Mato Grosso do Sul, Campo Grande, Brazil.
Vivek CharuQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Haley HedlinQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Di LuQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Amy ZhangQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Victor RitterQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Blake ShawQuantitative Sciences Unit, Biomedical Informatics Research Division, Stanford University School of Medicine, Stanford, California, USA.
Joelle I RosserInfectious Diseases and Geographic Medicine, Stanford Medicine, Stanford, California, USA.
Jessica Couvillion SeidmanAlbert B Sabin Vaccine Institute, Washington, District of Columbia, USA.ORCID https://orcid.org/0009-0005-1645-3789
Alice Scott CarterAlbert B Sabin Vaccine Institute, Washington, District of Columbia, USA.
Farah QamarDepartment Paediatric Infectious Diseases, The Aga Khan University, Karachi, Pakistan.
Stephen LubyInfectious Diseases and Geographic Medicine, Stanford Medicine, Stanford, California, USA.
Denise GarretAlbert B Sabin Vaccine Institute, Washington, District of Columbia, USA.
Julio CrodaFundação Oswaldo Cruz, Fiocruz Mato Grosso do Sul, Campo Grande, Brazil.ORCID https://orcid.org/0000-0002-6665-6825

Funding

Stanford Center for Clinical & Translational Education and Research (Spectrum)UL1TR003142 · NCATS · STANFORD UNIVERSITY · PI O'HARA, RUTH M · 2019 to 2023
$45.0M
Spectrum Stanford Center for clinical and Translational Research and EducationUL1TR001085 · NCATS · STANFORD UNIVERSITY · PI CULLEN, MARK RICHARD, GREENBERG, HARRY BERNARD · 2013 to 2017
$37.1M
NCATS NIH HHS UL1 TR001085NCATS NIH HHS UL1 TR003142
6 · The paper itself

Abstract

Objectives: To compare antispike IgG levels over a period of 182 days of follow-up in healthy adults who received full or fractional booster doses of BNT162b2 or AZD1222 after completing a primary series of Sinovac, BNT162b2 or AZD1222. Design: Double-blind, parallel-arm, phase IV randomised trial. Setting: The study was conducted in Campo Grande, Brazil, and participants were recruited in neighbourhoods with the lowest booster vaccine coverage. Follow-up visits were home based. Participants: 1451 (18-60 years) healthy adults who had received a full primary series of Sinovac (n=549), BNT162b2 (n=451) or AZD1222 (n=451) were included. Interventions: Participants were randomised to receive booster doses of either full or fractional doses of BNT162b2, AZD1222 or a full dose of Sinovac in the Sinovac-primed group. Antispike IgG antibody levels were measured at 0, 28, 84 and 182 days post-booster. Main outcome measures: Antispike IgG antibody levels were measured through blood samples at baseline and follow-up visits that were conducted 28, 84 and 182 days post-booster vaccination. Results: Throughout the 182-day follow-up period, full doses of BNT162b2 generated the highest antibody titres compared with fractional doses and other vaccines in all primary groups. Full-dose AZD1222 compared with its fractional dose showed a substantial difference only at day 28. BNT162b2 fractional doses produced higher antibodies than AZD1222 full doses. Sinovac-primed participants had the lowest baseline antibody titres, with Sinovac boosters continuing to show low titres, compared with BNT162b2 or AZD1222 full or fractional doses. Conclusions: Full doses of BNT162b2 consistently elicited higher antibody titres than fractional doses, AZD1222 and Sinovac at all time points. AZD1222 and Sinovac full doses produced lower titres than BNT162b2 fractional doses. Recommendations for using fractional doses of BNT162b2 as an alternative to full doses should be made cautiously, and further studies are needed to determine clinical protection levels. Trial registration number: NCT05343871.

Indexed as

COVID-19Public HealthSARS-CoV-2Vaccination

Identifiers

PMID40620571
PMCPMC12228459

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.