Abstract
Israel experienced a new wave of coronavirus disease during June 2021, six months after implementing a national vaccination campaign. We conducted 3 discrete analyses using data from a large health maintenance organization in Israel to determine whether IgG levels of fully vaccinated persons decrease over time, describe the relationship between IgG titer and subsequent PCR-confirmed infection, and compare PCR-confirmed infection rates by period of vaccination. Mean IgG levels steadily decreased over the 6-month period in the total tested population and in all age groups. An inverse relationship was found between IgG titer and subsequent PCR-positive infection. Persons vaccinated during the first 2 months of the campaign were more likely to become infected than those subsequently vaccinated. The vaccinated group >60 years of age had lower initial IgG levels and were at greater risk for infection. The findings support the decision to add a booster vaccine for persons >60 years of age.
Highlights
Israel experienced a new wave of coronavirus disease during June 2021, six months after implementing a national vaccination campaign
Israel was among the first countries to introduce a national vaccination campaign using the mRNA BNT162b2 vaccine (Pfizer-BioNTech, https://www.pfizer. com)
Effectiveness of mRNA BNT162b2 Vaccine, Israel reduced effectiveness of the vaccine against the Delta variant or a waning of protection provided by the vaccine over time
Summary
Israel experienced a new wave of coronavirus disease during June 2021, six months after implementing a national vaccination campaign. We conducted 3 discrete analyses using data from a large health maintenance organization in Israel to determine whether IgG levels of fully vaccinated persons decrease over time, describe the relationship between IgG titer and subsequent PCRconfirmed infection, and compare PCR-confirmed infection rates by period of vaccination. The vaccine campaign began on December 20, 2020 (concurrent with a 2-month nationwide lockdown), first targeting all healthcare workers and the population >60 years of age and quickly extending to all persons >16 years of age. The objective of this study was to determine if the BNT162b2 vaccine had become less effective in preventing infection, and if so, in which population groups and to what degree To meet this objective, we conducted 3 discrete analyses to answer the following questions. Do antibody levels (IgG) of those fully vaccinated decrease over time and if so, for who and how quickly? Second, what is the relationship between antibody level (IgG) and subsequent PCR-confirmed infection? Third, is there a difference in PCRconfirmed infection incidence rates between persons vaccinated in the initial months of the vaccination campaign and persons vaccinated later?
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
