# Mutation rates and transmission dynamics of influenza B virus

> **NIH NIH R21** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $195,000

## Abstract

Seasonal influenza epidemics result in significant morbidity and mortality and impose a large societal burden
associated with medical care and work loss. Approximately one third of influenza cases are due to influenza B
virus (IBV), and IBV is associated with more severe disease in children and higher rates of hospitalization than
seasonal A/H1N1 viruses. As in influenza A virus (IAV), the constant evolution and antigenic drift of IBV
necessitates annual updates in the two B lineage components of the quadrivalent vaccine. Phylogenetic
studies of viral sequences collected through global surveillance indicate that IBV has a slower rate of antigenic
evolution than IAV, yet the reason for these differences are unclear. Ultimately, the generation and early
transmission of novel variants is dependent on processes that take place on the scale of individual hosts. Very
little is known about these host-level dynamics in IBV. The long-term goal of this research is to elucidate the
molecular evolution of influenza viruses within hosts and to understand how novel variants spread between
them. The objective of this exploratory project is to determine the extent to which the differences in
evolutionary rates between IAV and IBV are explained by differences in the mutation rate, which determines
how rapidly new variants arise, and the transmission bottleneck, which determines how quickly a new variant
will move through host populations. The feasibility of the proposed research is supported by published
preliminary data, which demonstrate (i) the development of a novel and precise mutation rate assay that
provides unbiased estimates of each nucleotide substitution class, (ii) the assay's specificity and power for
distinguishing the rates of mutation for each nucleotide substitution class in closely related viruses, (iii) the use
of high quality next generation sequence (NGS) data of viruses from naturally infected individuals to identify
transmission pairs and to quantify the transmission bottleneck. Detailed analyses of host level IBV evolution
will be accomplished in two aims. (Aim 1) Determine the rates for all mutational classes in both B/Yamagata
and B/Victoria viruses. A novel and precise mutation rate assay will be used to define the rates for all 12
mutational classes in both IBV lineages. (Aim 2) Define the molecular genetics of transmission for influenza B
viruses in a community cohort. NGS of viruses from index cases and household contacts will be used to define
household transmission pairs and to quantify the size of the transmission bottleneck. This research is
innovative, because it will apply a newly developed assay to determine the mutation rates of IBV in
unprecedented detail and will leverage a unique household cohort to define the virus' transmission dynamics in
natural infection. The proposed research is significant, because it will define the evolutionary dynamics of IBV
at the level of the individual host and enable better predictive models...

## Key facts

- **NIH application ID:** 9878052
- **Project number:** 5R21AI141832-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Adam Lauring
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $195,000
- **Award type:** 5
- **Project period:** 2019-02-20 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9878052

## Citation

> US National Institutes of Health, RePORTER application 9878052, Mutation rates and transmission dynamics of influenza B virus (5R21AI141832-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9878052. Licensed CC0.

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