Wisconsin Rep. Paul Ryan — the freshly minted Republican vice presidential candidate — got an immediate ratings boost in the wake of his selection as Mitt Romney’s running-mate, according to a new Washington Post-ABC News poll.

Republican vice presidential candidate Rep. Paul Ryan, R-Wis., gives a thumbs-up at a rally Sunday, August 12, 2012, in Mooresville, N.C., at the NASCAR Technical Institute. (AP Photo/Jason E. Miczek)

In Wednesday through Friday interviews, fully 45 percent of Americans expressed no opinion of Ryan, dropping to 30 percent on Saturday and Sunday. The increasing familiarity all went to the positive side of the ledger, giving Ryan an initial advantage in the sprint to define his candidacy.

Overall, in interviews after his selection, 38 percent of all Americans express favorable views of Ryan, 33 percent negative ones. (Before the the announcement, Ryan was somewhat underwater, scoring 23 percent favorable, 32 unfavorable.) The most recent national numbers on Vice President Joe Biden are from a July Pew Research Center poll showing a split decision, 40 percent favorable, 37 percent unfavorable.

One of the largest movements on Ryan’s favorability numbers was the 21-point jump among conservative Republicans, but the initial movement was positive among independents as well, doubling from 19 to 39 percent. The shift among Democrats was similar in both a positive (up 10 percentage points on favorability) and negative direction (up eight on unfavorability).

(The Washington Post)

Before the announcement, senior citizens split 28 percent apiece positively and negatively on Ryan, but afterward his favorable number shot to 46 percent with no change on the other side of the equation. Seniors are likely to get even more outsized attention in the coming months due to Ryan’s controversial proposal to change the Medicare entitlement. A Post-Kaiser poll released over the weekend shows broad, cross-party opposition to such a change.

The Post-ABC survey included interviews with 667 randomly selected adults leading up to Saturday’s announcement, and 522 afterwards. The first three days of interviewing also included apparent GOP vice presidential contenders Ohio Sen. Rob Portman (who was unknown by nearly 60 percent of all Americans), former Minnesota governor Tim Pawlenty and Florida Sen. Marco Rubio.

Rubio -- the only one of the four to rival Ryan among conservative Republicans in the early numbers -- was also unknown by 45 percent of those surveyed.

Just 14 percent of conservative Republicans held “strongly favorable” views of Pawlenty before Saturday, well below the 36 percent who did so of Rubio and also below Ryan’s 24 percent. (Ryan’s “strong” number leapt to 44 percent after his selection.)