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Effectiveness, Immunogenicity and Safety of the Second Booster Dose of the Vaccine Against COVID-19 in the Elderly

NCT05283902 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 260

Last updated 2026-03-23

No results posted yet for this study

Summary

The objective of this observational case-crossover study is to evaluate the effectiveness, safety and immunogenicity of the second booster dose in the elderly. There are an estimated 490,000 eligible individuals aged 60 and over statewide for the effectiveness study. Two hundred and sixty participants will be invited to participate in biological sample for the immunogenicity study. This sub-sample will be compared with 260 biorepository samples from a cohort of immunosuppressed patients with autoimmune diseases who received the fourth dose, in a study conducted by the same team of researchers. The main effectiveness outcome will be the number of hospitalizations; and secondary outcomes will be deaths, number of reported cases, number of cases confirmed by RT-PCR. The safety assessment will be carried out by monitoring adverse events. The cellular and humoral immune response will be evaluated by viral neutralization assay (search for neutralizing antibodies), serological assay by chemiluminescence, determination of specific IgM and IgG profile, dosage of soluble systemic factors (chemokines, cytokines and growth factors), stimulation in vitro antigen-specific peripheral blood mononuclear cells and investigation of memory T and B lymphocytes and intracytoplasmic cytokines. The study hypothesis is that elderly people who received the second booster dose have a lower incidence rate of hospitalizations and death than those who received the primary regimen (two doses or one of Janssen) or a booster dose, and that the immune response humoral and cellular function of the elderly is similar to those who are immunosuppressed.

Conditions

  • COVID-19
  • Vaccine Adverse Reaction
  • Vaccine-Preventable Diseases

Interventions

BIOLOGICAL

ChAdOx1 nCoV-19 or Comirnaty or Janssen COVID-19 Vaccine

In a Technical Note, the State of Espírito Santo decided to recommend the application of the fourth dose with vaccines using messenger RNA (mRNA) technology or viral vector vaccine, for all people aged 60 years or older, with an interval of 90 days from of the third dose, considering that, while there is no availability of vaccines adapted to the new variants, boosters with available vaccines are still the most appropriate ways to prevent hospitalization and deaths.

Sponsors & Collaborators

  • Secretaria de Estado da Saúde do Espírito Santo - SESA

    collaborator UNKNOWN

  • Centro de Pesquisas René Rachou

    collaborator OTHER_GOV

  • Federal University of Espirito Santo

    lead OTHER

Eligibility

Min Age
60 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2022-03-19
Primary Completion
2022-06-01
Completion
2022-10-01

Countries

  • Brazil

Study Locations

More Related Trials

Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05283902 on ClinicalTrials.gov