Employers weighing whether to follow Delta Air Lines' lead and impose financial penalties on their unvaccinated employees could charge an unlimited amount depending on the type of wellness plan they choose.

The airline said this week that it will institute a $200 monthly surcharge on health insurance premiums for employees who haven't received a Covid-19 vaccine by November 1. Rather than imposing vaccine mandates, dozens of companies are contemplating similar surcharges on premiums, while others are taking a wait-and-see approach, according to employee benefits consultants and others who work on health insurance matters.

Delta's move came in the wake of the Food and Drug Administration's (FDA's) full approval of the Pfizer-BioNTech vaccine and as Covid cases and hospitalizations have increased dramatically in recent months due to the highly transmissible delta variant. Each hospitalization comes with significant costs for employers. The airline said the average hospital stay for Covid-19 had cost it $50,000 per person.