The partisan battle over vote-by-mail in the 2020 election is raising questions about how absentee voting will affect political participation and election outcomes during the COVID-19 pandemic. We study this question using administrative data from Texas’s July 14th primary runoff, where only people 65 and older could vote absentee without an excuse. Despite concerns that COVID-19 would depress turnout in the absence of absentee voting, we find that the turnout gap between 64 and 65 year olds did not markedly increase during COVID-19, even as the rate of absentee voting tripled relative to previous runoffs. While we find that the gap in rates of absentee voting is three times larger for Democrats than Republicans during the pandemic, high rates of in-person voting by Republicans offset this increase, leaving the partisan composition of turnout unchanged from past runoffs. Though extrapolating these results requires caution, they suggest that expanding absentee voting during the pandemic may cause large numbers of voters to shift to a more health-preserving mode of voting, without necessarily changing election outcomes even despite major partisan differences in enthusiasm for absentee voting.