Wednesday, February 18, 2026 2/18/2026

Within and between host dynamics in influenza A virus antigenic evolution

Award Number: F31AI179207
ORGANIZATION: NATIONAL INSTITUTE OF ALLERGY & INFECTIOUS DISEASES
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: FELLOWSHIP/SCHOLARSHIP/STUDENT LOANS
PERIOD OF PERFORMANCE START DATE: 05/01/2024
PERIOD OF PERFORMANCE END DATE: 04/30/2027

Group Awards By:

View Award Description

Within and between host dynamics in influenza A virus antigenic evolution - PROJECT SUMMARY/ABSTRACT Seasonal influenza A viruses (IAVs) cause several million infections each year in the United States and have significant economic and health impacts. The rapid evolution of IAVs yields antigenically distinct viruses each year. Vaccine strains are chosen several months prior to the start of the season, but given the high rate of viral evolution, predominant strains can change between when vaccine strains are chosen and the start of the season. This poses as a major challenge in designing effective vaccines. A better understanding of how antigenic variants arise will improve the ability to anticipate antigenically distinct IAVs. At the global level, there is a clear pattern of recurring selective sweeps where antigenically novel variants that escape pre-existing humoral responses dominate in circulation. However, at the individual host level, stochastic effects appear to play a greater role in shaping IAV evolution. Yet antigenic mutants must arise amongst individuals to circulate globally. Data from the Lowen laboratory and other groups suggest that transmission may play a role in selecting for IAVs. Based on these data, I hypothesize that selection of IAV antigenic mutants in the context of pre-existing immunity acts inefficiently within hosts but efficiently during transmission between hosts. I will be using genetically barcoded influenza A/Texas/50/2012 (H3N2) virus (Tx/12) to address this hypothesis. Tx/12 is a well-studied virus that was the chosen vaccine strain for the 2014-2015 influenza season. The circulating H3N2 viruses during this season however were antigenically mismatched to the vaccine Tx/12 strain. This resulting vaccine escape was a result of the F159S mutation in the hemagglutinin (HA) glycoprotein. I will use genetically neutral barcoded Tx/12 wild type and HA F159S viruses in pre-immunized guinea pigs (i.e., pre-immune) to determine how both deterministic and stochastic effects shape the antigenic evolution of IAV. I have rescued non-barcoded Tx/12 wild type and HA F19S virus using reverse genetics. I have shown that both viruses grow robustly in guinea pigs and the HA F159S virus is antigenically distinct from the wild type virus in the guinea pigs. I have also designed and begun cloning the genetic barcodes in the HA genes of both viruses and started evaluating the vaccine to induce partial pre-existing immunity to Tx/12 wild type virus in guinea pigs. In Aim 1, I will examine the efficiency of selection within pre-immune hosts. I will alter the time of introduction of the antigenic mutant and its frequency in the population. I will monitor wild type and antigenic mutant barcode frequencies and diversity to measure genetic bottlenecks under these conditions. In Aim 2, I will examine the efficiency of selection between hosts. I will alter whether the donor or recipient animal has partial pre-existing immunity to Tx/12 wild type and monitor barcode frequencies and diversity of both viruses in donor and recipient animals. Through these experiments, I will further our fundamental understanding of the evolutionary processes that govern IAVs which can aid in better anticipating seasonal variants when designing vaccines.


Issue Date FY	Funding FY	Legal Entity Name	Legal Entity Address	Legal Entity City	Legal Entity State	Legal Entity Zip Code	Legal Entity COUNTY	Legal Entity COUNTRY	Assistance Listing	Award Code	Budget Year	Action Date	Action Type	Action Amount

Issue Date FY: 2025 ( Subtotal = $49,538 )
2025	2025	EMORY UNIVERSITY	201 DOWMAN DR NE	ATLANTA	GA	30322	DEKALB	USA	Allergy and Infectious Diseases Research	000	2	4/16/2025	NON-COMPETING CONTINUATION	$48,974
2025	2025	EMORY UNIVERSITY	201 DOWMAN DR NE	ATLANTA	GA	30322	DEKALB	USA	Allergy and Infectious Diseases Research	001	2	8/1/2025	NON-COMPETING CONTINUATION	$564
														Subtotal = $49,538

Issue Date FY: 2024 ( Subtotal = $48,974 )
2024	2024	EMORY UNIVERSITY	201 DOWMAN DR NE	ATLANTA	GA	30322	DEKALB	USA	Allergy and Infectious Diseases Research	002	1	5/8/2024	NEW	$1,280
2024	2024	EMORY UNIVERSITY	201 DOWMAN DR NE	ATLANTA	GA	30322	DEKALB	USA	Allergy and Infectious Diseases Research	001	1	3/21/2024	NEW	$0
2024	2024	EMORY UNIVERSITY	201 DOWMAN DR	ATLANTA	GA	30322	DEKALB	USA	Allergy and Infectious Diseases Research	000	1	3/21/2024	NEW	$47,694
														Subtotal = $48,974

Grand Total All Awards = $98,512

Top

All Categories

About

Search

Reports

Data Submission

Award Information

Within and between host dynamics in influenza A virus antigenic evolution

Award Number: F31AI179207

ORGANIZATION: NATIONAL INSTITUTE OF ALLERGY & INFECTIOUS DISEASES

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

AWARD ACTIVITY TYPE: FELLOWSHIP/SCHOLARSHIP/STUDENT LOANS

PERIOD OF PERFORMANCE START DATE: 05/01/2024

PERIOD OF PERFORMANCE END DATE: 04/30/2027

Federal Websites

Department of Health & Human Services

HHS Operating Divisions

HHS Staff Divisions

Download A Document Viewer