Seventeen members of a British family say they have contracted COVID-19 after attending the funeral of an elderly relative who died of disease.

One of those attending the funeral also has since died, Yahoo News UK reports.

The family attended the funeral in early March before the U.K. government imposed social distancing standards, and they now are urging other families to be aware and take the guidelines seriously.

Eighty-six-year-old Sheila Brooks died in February and her memorial service was held two weeks ago, attended by extended family. Shortly afterward, her 65-year-old niece Susan Nelson, fell ill with suspected coronavirus and died.

Sixteen other family members have the virus as well, including her husband and daughter.

"The speed it acts at is phenomenal and how vicious it is can't be underestimated," Susan’s son Carl, told YahooNews UK. "Don’t be stupid and don’t risk it."

Carl was not allowed to be with his mother at the hospital as she died because he didn't show symptoms himself, nor was his sister, who has an underlying condition putting her at extra risk. Only her husband was allowed to comfort her as she died.

"I had to tell her they wouldn't let me come and I wasn’t allowed to see her, he said. "I didn't want her to die thinking that I didn't want to come."

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