Tennessee has been chosen as one of four states in Pfizer’s pilot program to deliver its coronavirus vaccine. The drug company announced last week that its vaccine had been more than 90% effective in phase three trials.

Pfizer is facing distribution challenges due to its ultra-cold storage requirements. The vaccine must be kept at minus 70 degrees Celsius (minus 94 Fahrenheit).

Gov. Bill Lee said in a tweet Tuesday that Tennessee was chosen because of the state’s ability to build out a strong infrastructure.

We thank @Pfizer for including Tennessee as one of four pilot states to partner in delivering and deploying a COVID-19 vaccine. Pfizer selected our state because of our ability to build out a strong infrastructure and we are thankful for their partnership.https://t.co/6oqhABvpaR

— Gov. Bill Lee (@GovBillLee) November 17, 2020

Rhode Island, Texas and New Mexico were also chosen for that reason, according to Reuters, and because of the states’ differences in overall size, diversity of populations and the need to reach people in urban and rural areas.

Being in the pilot program does not mean these places will receive the vaccine doses earlier than other states. Pfizer has a nearly $2 billion deal with the federal government to supply 100 million doses of the vaccine — with an option to add up to 500 million more. The company expects to apply for emergency use authorization by the end of this month.