Paul Pepe, MD, MPH, FAEMS,MCCM
Global Coordinator, Metropolitan EMS Medical Directors Alliance
University of Texas Health Sciences, Houston, Texas, USA
Dallas, Texas
Disclosure information not submitted.
Peter Antevy, MD
Medical Director
City of Coral Springs, Parkland and Davie Fire Rescue Departments
Broward County, Florida, United States
Disclosure information not submitted.
Aileen Marty, MD, FACP
Distinguished University Professor in Infectious DIseases
Florida International University Herbert Wertheim College of Medicine
Miami, Florida, United States
Disclosure information not submitted.
Jonathan Jui, MD, MPH, FACEP, FAEMS
EMS Medical Director, Multnomah County and Professor of Emergency Medicine
Oregon Health and Sciences University
Portlamd, Oregon, United States
Disclosure information not submitted.
Maricar Cabral, RN, CCRN
Pediatric Emergency Department
Joe DiMaggio Children’s Hospital
Hollywood, Florida, United States
Disclosure information not submitted.
Lauren Rosenberg, n/a
Study Coordinator
Coral Springs Parkland Fire Department
Coral Springs, Florida, United States
Disclosure information not submitted.
Remle Crowe, PhD
National Research Scientist
ESO
Austin, Texas, United States
Disclosure information not submitted.
Kenneth Scheppke, MD, FAEMS
State EMS Medical Director
Florida Department of Health
Tallahassee, Florida, United States
Disclosure information not submitted.
Title: Timing and Degree of Neutralizing Antibody Development after Pfizer-BioNTech Vaccination
Introduction: Most adults receiving mRNA vaccines for SARS-CoV-2 (SCV2) exhibit IgG antibodies (Ab) targeting the S1 spike protein within a week of dose 2. However, correlates of protection are still not fully understood. The aim of this study was to better quantify the % of neutralizing Ab (nAb) that develop after dose 2 and also identify factors affecting the timing and degree of nAb production.
Methods: Using a fluorescence immunoassay to quantify the % of SCV2-Ab capable of blocking S1 at its receptor binding domain (for attaching to ACE-2 receptors), residents/staff (n=70; ages 23-100 yrs) of an assisted living facility had blood samples measured on day 7 and 21 following dose 2 of the Pfizer-BioNTech mRNA vaccine. Based on existing research, %nAb < 30% is delineated as inadequate protection (“nAb negative”).
Results: Except for a 58 yo man taking daily prednisone (asthma) and a 55 yo man on levothyroxine, 100% of those < 70 yrs (n=33) were nAb+ ( >30% nAb) on day 7 after dose 2. However, if >70 yo (n=37), the % of nAb+ findings diminished with age. Only half of those 71-80 yo, 33% of those 81-90 yo and 11% of those >90 yo were nAb+. Nonetheless, 2 weeks later, the %+ among those tested had increased to 83%, 71%, and 50% for those respective age groups. When examining the average of nAb% measurements within each of the various age group stratifications 1 week after dose 2, the averages ranged 96-100% for the 3 age groups < 50 years (ie, 23-30, 31-40 and 41-50), while the age group averages were borderline or inadequate for those >70 yo. However, 21 days after dose 2, the average %nAb measurement had become 91% for those 61 to 70 years of age, 75% for those 71-80, and 55% for those 81-90. For persons > 90 yo (n=8), the average %nAb was 35% but half of those persons (n=4) had no detectable nAb, either at day 7 or day 21. No persons had any significant declines in %nAb between Day 7 and 21 and the majority sustained or improved their %nAb.
Conclusions: Escalating age and immunomodulating medications/conditions do impact the timing and degree of nAb developing after mRNA vaccination. Most persons < 90 yo are observed to be “positive” for protective levels of nAb by 3 weeks after dose 2. On-going investigations are addressing the duration and sustained degree of nAb+ findings as well as external validation of the tool used in this research.