Middlesbrough boss Neil Warnock wants the public to fully appreciate the seriousness of coronavirus, having recovered from the illness.
Warnock, 71, had to self-isolate away from the Championship club for 14 days after he tested positive for Covid-19.
The government has brought in tougher lockdown restrictions in the north east in response to a rising number of cases in the region.
"It's life and death with this horrible virus," Warnock said.
"That's why it annoys me when I see 200 kids having a party. It's not so much what's happening in their vicinity, it's what's going to happen in the wider area when they go and speak to somebody else and somebody else.
"They must have grandparents and parents that are older and have got problems. There's just not enough thought going on at times in certain areas, which disappoints me at the moment."
Warnock will return to the dugout for Saturday's game against Barnsley, having watched his side draw two games from afar.
"I was very fortunate I didn't get anything on my chest," Warnock added. "I just started with a little niggly throat and then lost my sense of smell and taste, and for the first few days (I was) absolutely shattered and wanting to go to sleep every minute of the day.
"You've got no option but to look after yourself. My son was with me as well, so he had to isolate as well, so it was strange.
"I didn't feel too bad (about being absent for) the games, if I'm honest, because I had conversations before, half-time and at the end, but it's nice to get back on the grass. It's always nice to have contact with your players and start talking about how you see the next game, etc."