None changes to Corona virus...it's a misconception...
The titre in widal can be often misleading as antibody produced in other viral infections may cross reacts with the antigens of salmonella...the causative agent of Thphoid fever.
But my suggestion will be any fever in this pandemic must be considered as COVID unless and until proven otherwise.
Next Steps
get your self tested for COVID RTPCR before starting a treatment of Thphoid
Health Tips
Manage the fever with PCM 650 ms 3 to 4 times a day before the reports of RTPCR comes.