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. 2022 Sep 19;17(9):e0269011.
doi: 10.1371/journal.pone.0269011. eCollection 2022.

COVID-19 cross-sectional study in Maricá, Brazil: The impact of vaccination coverage on viral incidence

Thiago Silva Frauches  1 , Carlos Alberto de Senna Costa  2 , Claudia Dos Santos Rodrigues  3 , Marcelo Costa Velho Mendes de Azevedo  4   5 , Michelle de Moraes Ferreira  5 , Hanna Beatriz Vieira da Silva Ramos  2 , Wilson Rodrigues de Souza Junior  1 , Andréa Ribeiro Costa  1 , Adriana Cardoso Camargo  1 , Adriana Halfeld Alonso  1 , Fábio Álvaro Dos Santos  1 , Hércules da Silva Oliveira  1 , Janaína Guimarães Coelho  1 , Joyce Florentina da Silva Sobral  1 , Luciane Cardoso Dos Santos Rodrigues  1 , Marcio Martins Casaes Ferreira  1 , Patricia Laureano  1 , Raquel Adalgiza da Paz Fernandes  1 , Renata da Silva Santos  1 , Rose Mary Carvalho Dos Santos  1 , Sanderson Milagres  1 , Vanessa Cristina Conceição Dos Santos  1 , Jussara Teixeira Silva  5 , Tatiana Martins da Silva  5 , Malu Gabriela Costa da Rocha  5 , Andreia Edwirges de São Carlos  5 , Amorim Mourão de Araújo Ramos  5 , Fernanda Martins de Almeida Bastos  5 , Daina Raylle Francisco  5 , Sabrina Dos Santos Rosa  5 , Layla Corrêa Linhares  5 , Raissa Rodrigues Organista  5 , Leandro Bastos  5 , Maria Magdalena Kelly Pinto  5 , Jean Pablo Lima do Nascimento  6 , João Pedro Moura da Silveira  6 , Mateus Quintanilha Dos Santos  6 , Nathaly Santos da Silva  6 , Nayra Cristina Dos Santos Ferreira  6 , Rafael Brito Ramirez Reis  6 , Ruan Fonseca de Oliveira  6 , Valdinei de Oliveira Sá  6 , Thyago Ramos de Siqueira Hammes  6 , Juliano de Oliveira Monteiro  6 , Pedro Henrique Cardoso  7 , Mônica Barcellos Arruda  7 , Patricia Alvarez  7 , Richard Araujo Maia  8 , Liane de Jesus Ribeiro  8 , Orlando Costa Ferreira Jr  8 , Aline Santos  9 , Alberto Carlos Melo de Almeida  9 , Lauro Garcia  10 , Celso Pansera  1 , Amilcar Tanuri  2   8
Affiliations

COVID-19 cross-sectional study in Maricá, Brazil: The impact of vaccination coverage on viral incidence

Thiago Silva Frauches et al. PLoS One. .

Abstract

Population surveillance in COVID-19 Pandemic is crucial to follow up the pace of disease and its related immunological status. Here we present a cross-sectional study done in Maricá, a seaside town close to the city of Rio de Janeiro, Brazil. Three rounds of study sampling, enrolling a total of 1134 subjects, were performed during May to August 2021. Here we show that the number of individuals carrying detectable IgG antibodies and the neutralizing antibody (NAb) levels were greater in vaccinated groups compared to unvaccinated ones, highlighting the importance of vaccination to attain noticeable levels of populational immunity against SARS-CoV-2. Moreover, we found a decreased incidence of COVID-19 throughout the study, clearly correlated with the level of vaccinated individuals as well as the proportion of individuals with detectable levels of IgG anti-SARS-CoV-2 and NAb. The observed drop occurred even during the introduction of the Delta variant in Maricá, what suggests that the vaccination slowed down the widespread transmission of this variant. Overall, our data clearly support the use of vaccines to drop the incidence associated to SARS-CoV-2.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Incidence of Covid-19 in the study.
A) Percentage of SARS-CoV-2 RT-PCR positive participants in all and each round of the study. B) N1 target Ct average of participants SARS-Cov-2 RT-PCR positive in all and each round of the study.
Fig 2
Fig 2. Percentage of anti-SCOV2 immunoglobulin positivity in each study cycle.
A, B and C) Anti-SCOV2 Immunoglobulin profile of unvaccinated participants. A) All vaccinated participants. B) <60 years old group. C) ≥60 years old group. White bars represent the 1st cycle, grey bars the 2nd cycle and black bars the 3rd cycle.
Fig 3
Fig 3. Comparisons among unvaccinated and fully immunized groups according to their anti-SCOV2 IgG and NAb levels.
A, B and C) Anti-SCOV2 IgG serum levels according to age (overall, <60 and ≥60 years old, respectively). D, E and F) NAb serum levels of overall, <60 and ≥60 years old groups, respectively. Red line represents the cut offs (≥1.0 and ≥70%). Blue lines stands for the median of each group. Red dots represent SARS-CoV-2 RT-PCR positive individuals in each group. * p value <0.05; **** p value <0.0001.
Fig 4
Fig 4. Fully vaccinated groups distribution.
A) Distribution of CoronaVac and AstraZeneca fully vaccinated groups according to time after the end of immunization scheme. B) Age distribution of CoronaVac and AstraZeneca fully vaccinated groups.
Fig 5
Fig 5. Impact of immunization on COVID-19 incidence on the studied population.
On the left Y axis: red line shows de COVID-19 incidence on the studied population over the three round. On the right Y axis: 1) black line represents the percentage of vaccinated participants through the three rounds; 2) blue line shows the percentage of SCOV2 IgG+ individuals (IgG OD/CO >1.0); 3) dotted blue line points the percentage of SCOV2 IgG+ individuals carrying detectable levels of NAb. Black, grey, and white bars represent the frequency of Delta (Δ), Gamma (γ) and other VOCs, respectively, in the city of Maricá when all three rounds were performed.
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Supplementary concepts