All Philadelphians 16 and older are now eligible and would be getting their first Pfizer dose.
"The past few days- it's been inclement weather, it's been a little bit colder, so we've seen fewer folks trying to take advantage of these walk-up opportunities," said Charlie Elison of FEMA, which runs the site.
RELATED: All Philadelphia residents 16+ now eligible to receive a COVID-19 vaccine
When doors opened on Friday morning lines were low.
"The bottom line is, up until 5 pm, we're doing walk-ups, and we will not close our doors to anyone who is outside," Elison said.
Now Pfizer's CEO, Albert Bourla, says people will "likely" need a third shot or booster dose of a COVID vaccine within 6 to 12 months of being fully vaccinated.
RELATED: Pfizer CEO says annual COVID-19 vaccines may be necessary
He added that it is possible that people will need to get re-vaccinated every year.
"It's not a surprise at all. If that's what we have to do to stay safe, then that's what we have to do," said Chris Aglesta of Fitlers Square, who just received her first dose.
"It's not very surprising to me. I guess there is definitely a concern with anti-vax sentiment and sort of what that's going to mean for the rest of the people in the city," added Shelby Billups of Center City, who just got her first dose.
So would enough people do it?
"I think it's important for the community to keep people safe. If that's what it takes then I'm willing to do it," said Tim Eason of Manayunk.
"I do what my doctor tells me to do," remarked Suzanne Stunn of Roxborough.
The Esperanza site in Hunting Park is closed on Friday, but there will also be hundreds of walk-ups slots there on Saturday.