Mavis TOPLIS ?-1918

Mavis TOPLIS was the first born child of Ernest Vincent O'NEILL and Florence TOPLIS.
She died as an infant in 1918. I have received the death certificate for Mavis, but i cannot locate it at the moment. Her cause of death was infantile tetanus. The certificate states she was 7 years old, but that does not make any sense at all. It was more likely seven days old.
As a side note, I've found that the Queensland certificates are full of transcription errors.