She recently went public on social media to share her story of being diagnosed with pericarditis, inflammation of the sac around the heart, after being injected with a second dose of a COVID-19 shot.

She doesn't mention the manufacturer of the shot, but the government of New Zealand's pamphlet on "COVID-19 Vaccine" only mentions Pfizer, and no other brand. https://www.health.govt.nz/system/files/documents/pages/covid-19-vaccine-what-to-expect-20oct2021.pdf

While these tragic stories of people being injured, especially with heart issues, following COVID shots are all too common these days, what is remarkable about Stallone's story is what she learned after being admitted to the hospital, and realizing that these vaccine injuries are not rare at all.