Instruct: Identify the main category of Medrxiv papers based on the titles and abstracts
Query: A booster dose of an inactivated SARS-CoV-2 vaccine increases neutralizing antibodies and T cells that recognize Delta and Omicron variants of concern BackgroundCoronaVac(R) is an inactivated SARS-CoV-2 vaccine approved by the World Health Organization. Previous studies reported increased levels of neutralizing antibodies and specific T cells two- and four-weeks after two doses of CoronaVac(R), but the levels of neutralizing antibodies are reduced at six to eight months after two doses. Here we report the effect of a booster dose of CoronaVac(R) on the anti-SARS-CoV-2 immune response generated against variants of concern (VOC) Delta and Omicron in adults participating in a phase 3 clinical trial in Chile.

MethodsVolunteers immunized with two doses of CoronaVac(R) in a four-week interval received a booster dose of the same vaccine between twenty-four and thirty weeks after the 2nd dose. Four weeks after the booster dose, neutralizing antibodies and T cell responses were measured. Neutralization capacities and T cell activation against VOC Delta and Omicron were detected at four weeks after the booster dose.

FindingsWe observed a significant increase in neutralizing antibodies at four weeks after the booster dose. We also observed an increase in CD4+ T cells numbers over time, reaching a peak at four weeks after the booster dose. Furthermore, neutralizing antibodies and SARS-CoV-2 specific T cells induced by the booster showed activity against VOC Delta and Omicron.

InterpretationOur results show that a booster dose of CoronaVac(R) increases the anti-SARS-CoV-2 humoral and cellular immune responses in adults. Immunity induced by a booster dose of CoronaVac(R) is active against VOC, suggesting an effective protection.
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The categories of this paper are: sexual
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The categories of this paper are: geriatric
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The categories of this paper are: genomic
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The categories of this paper are: research
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The categories of this paper are: nutrition
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The categories of this paper are: critical
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The categories of this paper are: rehabilitation
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The categories of this paper are: epidemiology
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The categories of this paper are: psychiatry
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The categories of this paper are: otolaryngology
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The categories of this paper are: endocrinology
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The categories of this paper are: obstetrics
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The categories of this paper are: pharmacology
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The categories of this paper are: immunology
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The categories of this paper are: oral
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The categories of this paper are: surgery