Always ask questions to make them ‘look stupid’ or even start questioning their own source. Try to avoid hitting them with too many rebuttals, especially at first.

Ask them about the studies and the data to support that claim. Also, who are funding those studies?

I have a feeling many of those with ‘long Covid’ problems were also vaccinated.

If they are still just regurgitating the mass psychosis narrative, remind them that there are numerous other side effects of the vaccine that cause the risk to outweigh the benefit. There are hundreds if not thousands of studies (https://www.informedchoiceaustralia.com/post/1000-peer-reviewed-studies-questioning-covid-19-vaccine-safety) which call question to the vaccine safety.