Hi,
No you cannot but the health checks barely cost anything:
Basic health checks (Azure) $0.36 per Azure endpoint/month
You can switch off Health Checks if you use Front Door instead of Traffic Manager, however the Front Door Standard costs $35/month and probably won't fit your needs.
If you think about it: The point of the health checks is that Traffic Manager can switch over, so if you don't have checks there is really no point in Traffic Manager and you may want to look at a different mechanism altogether.
Hope this clarifies.
See also
https://github.com/uglide/azure-content/blob/master/articles/traffic-manager/traffic-manager-monitoring.md
https://azure.microsoft.com/en-gb/pricing/details/frontdoor/
https://azure.microsoft.com/en-gb/pricing/details/traffic-manager/