Five of the nearly 60 Texas Democrats who fled Texas last week in an effort to prevent the passage of a restrictive new voting law have tested positive for the coronavirus in Washington, including two cases announced on Sunday.

All five lawmakers are fully vaccinated and were experiencing mild or no symptoms, the Texas House Democratic Caucus said in a statement. It said all caucus members and their staff in Washington were being tested daily.

Two of those who tested positive have identified themselves. State Representative Trey Martinez Fischer said he tested positive on Sunday. In a statement, he said he had “extremely mild” symptoms and would quarantine until he tested negative.

Another lawmaker, State Representative Celia Israel, said she tested positive on Saturday.

The first lawmaker to test positive reported it on Friday night. Ms. Israel and another colleague tested positive on Saturday.

The Democratic lawmakers left Texas for Washington on July 12, shortly after the start of a 30-day special session to secure passage of the voting bill, among other Republican priorities. They have vowed to stay in the capital until the special session concludes, denying a quorum to the Republican majority that sponsored the bill.

The proposed law includes restrictions on absentee voting and bans 24-hour and drive-through voting, which are disproportionately used by Democrats. Gov. Greg Abbott, a Republican, has threatened to arrest the Democratic lawmakers once they return to the state.

State Representative Gene Wu, one of the Democrats now in Washington, said the positive tests underscored the importance of getting inoculated against the virus, especially as the more contagious Delta variant continues to spread.

“That is the beauty of being vaccinated,” he told MSNBC on Saturday. “Every single person who has tested positive so far have little to no symptoms, which is sort of the point of the vaccine. And if nothing else, we would want this to be a reminder to all Americans, get your stupid shots now. Don’t wait.”

The Covid vaccines in use in the United States have proven to be effective at reducing the risk of severe symptoms or hospitalization, but infections among fully vaccinated individuals, known as breakthrough infections, are not unheard of. It is not yet clear whether the highly transmissible Delta variant circulating across the country increases the likelihood of breakthrough infections.