The SARS-CoV-2 virus causes severe respiratory illness and is an ongoing global pandemic. On December 12, 2020 the FDA approved Pfizer's BioNTech vaccine BNT162b2 which is a messenger RNA type of vaccine for use. This vaccine has shown in numerous studies the ability to induce a strong immune response and provide both humeral and cellular protection against wild type, alpha and delta variants of SARS-CoV2 virus. In Israel the national vaccine operation began in mid-December 2020 which included 2 initial doses three weeks apart. In August 2021 a first booster (3rd dose) was provided to enhance protection and due to reports of reduced immune response and clinical protection. Several studies have demonstrated that over time there is a decay in the antibody levels, and with them reduced protection. Recently a new variant of concern has been identified (Omicron) and is causing a surge of infections worldwide. There is lack of knowledge regarding the effectiveness of the current schedule of vaccine against this new variant and whether a second booster (4th dose) will provide higher levels of clinical protection against this variant, currently the ministry of health is considering recommendations for a fourth dose for HCW. The purpose of this study is to examine whether a fourth dose of vaccination will provide better protection against infection and clinical disease.
Study Type
OBSERVATIONAL
Enrollment
635
The Pfizer-BioNTech COVID-19 vaccine (INN: tozinameran), sold under the brand name Comirnaty, is an mRNA-based COVID-19 vaccine developed by the German biotechnology company BioNTech. For its development, BioNTech collaborated with American company Pfizer to carry out clinical trials, logistics, and manufacturing. It is authorized for use in people aged five years and older in some jurisdictions, twelve years and older in some jurisdictions, and for people sixteen years and older in other jurisdictions, to provide protection against COVID-19, caused by infection with the SARS-CoV-2 virus. The vaccine is given by intramuscular injection. It is composed of nucleoside-modified mRNA (modRNA) encoding a mutated form of the full-length spike protein of SARS-CoV-2, which is encapsulated in lipid nanoparticles. Initial advice indicated that vaccination required two doses given 21 days apart, but the interval was later extended to up to 42 days in the US, and up to four months in Canada
Soroka UMC
Beersheba, Israel
Proportion of positive PCR test for SARS-COV2
Percent Positive PCR test
Time frame: 30 days
Proportion of positive PCR test for SARS-COV2
Percent Positive PCR test
Time frame: 60 days
Proportion of positive PCR test for SARS-COV2
Percent Positive PCR test
Time frame: 90 days
Proportion of positive PCR test for SARS-COV2
Percent Positive PCR test
Time frame: 120 days
Proportion of positive PCR test for SARS-COV2
Percent Positive PCR test
Time frame: 150 days
Proportion of symptomatic COVID 19 infection
Percent Positive PCR test
Time frame: 30 days
Proportion of symptomatic COVID 19 infection
Percent Positive PCR test
Time frame: 90 days
Proportion of symptomatic COVID 19 infection
Percent Positive PCR test
Time frame: 182 days
Proportion of COVID 19 infection requiring hospitalization
Percent Positive PCR test
Time frame: 30days
Proportion of COVID 19 infection requiring hospitalization
Percent Positive PCR test
Time frame: 90 days
Proportion of COVID 19 infection requiring hospitalization
Percent Positive PCR test
Time frame: 182 days
Levels of binding and neutralizing activity and avidity of the antibodies
binding antibody units per mL
Time frame: 30 days
Levels of binding and neutralizing activity and avidity of the antibodies
50 Percent neutralization titer
Time frame: 60 days
Levels of binding and neutralizing activity and avidity of the antibodies
50 Percent neutralization titer
Time frame: 90 days
Levels of binding and neutralizing activity and avidity of the antibodies
50 Percent neutralization titer
Time frame: 120 days
Levels of binding and neutralizing activity and avidity of the antibodies
50 Percent neutralization titer
Time frame: 150 days
Levels of binding and neutralizing activity and avidity of the antibodies
50 Percent neutralization titer
Time frame: 180 days
Composite endpoint of serious adverse events
Percent Positive Anaphylaxis, Myocarditis
Time frame: 14 days following the booster vaccination
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