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NCT Number: NCT05283902

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

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.

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Key information

Conditions

COVID-19 Coronaviridae Infections Coronavirus Infections Infections Lung Diseases Nidovirales Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Vaccine Adverse Reaction Vaccine-Preventable Diseases Virus Diseases

Age range

60 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Valéria Valim

Vitória, Espírito Santo, 29041-295, Brazil

About this study

Faced with the new scenario of high transmission of the Ômicron variant of SARS-COV-2, in which the elderly over 60 years and immunosuppressed even vaccinated with three doses have become a population vulnerable to a greater probability of serious illness by Covid-19, demanding an increase in risk of hospitalization and deaths, the application of the fourth dose (second booster dose) has become an alternative to increase protection for these individuals. The general objective of this study is to evaluate the effectiveness, safety and immunogenicity of the second booster dose in the elderly. This is an observational, case-crossover study, based on databases with notification and vaccination records and a cohort study for the analysis of immunogenicity. Elderly people of both sexes aged 60 years or older, residents of Espírito Santo, will be included. There are an estimated 490,000 eligible individuals aged 60 and over statewide for the effectiveness study. Two hundred and sixty participants, with quotas distributed by sex (50% male and 50% female) and age group, will be invited to participate in biological sample collection on the day of application of the second booster dose (T1) , 28 days after the second booster dose (T2), at the follow-up visit after 3 months (T3), 150 days (T4) and 180 days (T5), for follow-up of vaccine response and follow-up of duration of immunity, in a health unit in Cariacica-ES. This sub-sample will be compared with 240 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, weighted by protection time, 90 days after complete immunization (14th day after second booster dose); 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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age equal to or greater than 60 years
  • Residents of Espírito Santo, Brazil

Exclusion criteria

  • Being under active treatment (chemotherapy and/or radiotherapy) for the treatment of any type of neoplasm
  • Being admitted to an institutionalization establishment for the elderly (hospitals, nursing homes, shelters or similar).
  • Patients with mental illness with inability to understand the consent form

Treatment and study plan

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

Biological

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.

Primary outcomes

  1. number of hospital admissions

    Time frame: Change from baseline at 6 months

    number of hospital admissions for covid-19 recorded in the "e-SUS notifica"

  2. Number of adverse events

    Time frame: Change from baseline at 1 month

    Surveillance of adverse post-vaccine events (PVAE) and adverse events of special interest (EAIE) recorded in the "e-SUS notifica"

Secondary outcomes

  1. number of deaths

    Time frame: Change from baseline at 6 months

    Number of deaths with specific ICD for covid-19 recorded in the "e-SUS notifica"

  2. number of Covid-19 cases

    Time frame: Change from baseline at 6 monhts

    number of Covid-19 cases confirmed by RT-PCR recorded in the "e-SUS notifica"

  3. Viral neutralization assay

    Time frame: Change from baseline at 1, 3, 5 and 6 months

    Neutralizing antibody titers will be expressed by the ability of antibodies to neutralize up to 50% the number of plaques (PRNT50). Title > 1:50 will be considered positive.

  4. Serological assay

    Time frame: Change from baseline at 1, 3, 5 and 6 months

    Serological test by chemiluminescence for qualitative and quantitative determination of specific IgG antibodies against the nucleocapsid protein of SARS-Cov-2. Results are expressed in U/mL and data interpretation will be done as follows: <0.8 U/mL = non-reactive sample; ≥0.8 U/mL = reactive sample.

  5. Soluble systemic factors

    Time frame: Change from baseline at 1, 3, 5 and 6 months

    Dosage of soluble systemic factors (chemokines, cytokines and growth factors). Results will be expressed in pg/ml.

  6. Lymphocyte investigation

    Time frame: Change from baseline at 1, 3, 5 and 6 months

    Investigation of memory T and B lymphocytes. The results will be expressed in percentage positive frequency for a specific cell phenotype.

  7. Cytokine investigation

    Time frame: Change from baseline at 1, 3, 5 and 6 months

    Investigation of intracytoplasmic cytokines. The results will be expressed in percentage positive frequency for a specific cell phenotype.

Sponsors and collaborators

Lead sponsor

Federal University of Espirito Santo

Other

Collaborators

  • Centro de Pesquisas René Rachou
  • Secretaria de Estado da Saúde do Espírito Santo - SESA

Registry information

Official study title

Effectiveness, Immunogenicity and Safety of the Second Booster Dose (Fourth Dose) of the Vaccine Against COVID-19 in the Elderly: Study Reforça Mais (Plus Booster)

Acronym: Plus_Booster

Important dates

Study start
2022
Primary completion
2022
Study completion
2022
First posted
Mar 17, 2022
Registry last updated
Mar 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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