Our adjusted FFO of $0.85 per share, and our funds available for distribution of $0.81 per share allowed us to maintain our quarterly dividend of $0.67 per share.
The payout ratio is 79% of adjusted FFO and 83% of funds available for distribution.
Over the last six months, we have issued $1.4 billion in bonds, and we have recast our $1.5 billion bank credit facility with a four-year maturity in 2025.
With an estimated $24.5 billion remaining in the Provider Relief Fund and the likelihood of provider funding requests well in excess of this amount, we expect certain providers in the industry may have shortfalls.
Based on operators representing over 90% of our facilities reporting in, the vaccination rate for residents is approximately 81% with the vaccination rate for staff at approximately 49%.
This is a vast improvement over what we reported last quarter of 69% and 36% for residents and staff, respectively.
Our NAREIT FFO for the quarter was $170 million or $0.71 per share on a diluted basis as compared to $181 million or $0.77 per share for the first quarter of 2020.
Revenue for the first quarter was approximately $274 million before adjusting for nonrecurring items.
The revenue for the quarter included approximately $12 million of noncash revenue.
We collected over 99% of our contractual rent, mortgage and interest payments for the first quarter, as well as for the month of April.
Our G&A expense was $10.4 million for the first quarter of 2021, in line with our estimated quarterly G&A expense of between $9.5 million and $10.5 million.
Interest expense for the quarter was $56 million.
In March, we issued $700 million of 3.25% senior notes due April 2033.
Our note issuance was leverage neutral as proceeds were used to repurchase through a tender offer, $350 million of 4.375% notes due in 2023 and to repay LIBOR-based borrowings.
As a result of the repurchase, we recorded approximately $30 million in early extinguishment of debt cost.
At March 31, we had $135 million in borrowings outstanding under our $1.25 billion credit facility, which matured at the end of the month, and $50 million in borrowings under a term loan facility that had a maturity in 2022.
On April 30, we closed a new $1.45 billion unsecured credit facility and a $50 million unsecured term loan facility that both mature in April of 2025.
In March of 2020, we entered into $400 million of 10-year interest rate swaps at an average swap rate of 0.8675%.
The repurchase of 50% of our 2023 bonds and the completion of the credit facility and term loan transactions extended our debt maturities, improved our overall borrowing cost and reinforced our liquidity position.
In the first quarter, we issued 2 million shares of common stock through a combination of our ATM and dividend reinvestment and common stock purchase plan, generating $76 million in cash proceeds, but we believe our actions to date provide us with flexibility to weather a potential prolonged impact of COVID-19 on our business.
At March 31, approximately 97% of our $5.5 billion in debt was fixed, and our funded debt to adjusted annualized EBITDA was approximately 5.2 times, and our fixed charge coverage ratio was 4.5 times.
When adjusting to include a full quarter of contractual revenue for new investments completed during the quarter, as well as eliminating revenue related to assets sold during the quarter, our pro forma leverage would be roughly 5.1 times.
As of March 31, 2021, Omega had an operating asset portfolio of 954 facilities with over 96,000 operating beds.
These facilities were spread across 70 third-party operators, located within 41 states and the United Kingdom.
Trailing 12-month operator EBITDARM and EBITDAR coverage for our core portfolio as of December 31, 2020, stayed relatively flat for the period at 1.86 times and 1.5 times, respectively, versus 1.87 times and 1.51 times, respectively, for the trailing 12-month period ended September 30, 2020.
During the fourth quarter, our operators cumulatively recorded approximately $115 million in federal stimulus funds as compared to approximately $102 million recorded during the third quarter.
Trailing 12-month operator EBITDARM and EBITDAR coverage would have decreased during the fourth quarter of 2020 to 1.38 and 1.04 times, respectively, as compared to 1.53 and 1.18 times, respectively, for the third quarter when excluding the benefit of the federal stimulus funds.
EBITDAR coverage for the stand-alone quarter ended 12/31/2020 for our core portfolio was 1.33 times, including federal stimulus, and 0.78 times, excluding the $115 million of federal stimulus funds.
This compares to the stand-alone third quarter of 1.44 times and 0.97 times with and without the $102 million in federal stimulus funds, respectively.
Cumulative occupancy percentages for our core portfolio were at a pre-COVID rate of 84% in January 2020.
While they flattened out to around 75% throughout the fall months, they subsequently fell to 73.3% in December and further in January to 72.3% before starting to show signs of recovery at 72.6% in February and 73.1% in March.
Based upon what Omega has received in terms of occupancy reporting for April to date, occupancy has continued to improve, averaging approximately 73.4%.
As previously announced, on January 20, 2021, Omega closed on the purchase of 24 senior housing facilities from Healthpeak for $510 million.
The portfolio primarily consists of assisted living, independent living and memory care facilities with a total of 2,552 units located across 11 states.
The master lease with Brookdale will generate approximately $43.5 million in contractual 2021 cash rent with annual escalators of 2.4%.
Additionally, during the first quarter of 2021, Omega completed an $83 million purchase lease transaction for six skilled nursing facilities in Florida.
The facilities were added to an existing operator's master lease for an initial cash yield of 9.25% with 2.25% annual escalators.
Omega's new investments for the quarter totaled $610 million, inclusive of $17 million in capital expenditures.
During the first quarter of 2021, Omega divested 24 facilities for total proceeds of approximately $188 million.
As Taylor previously mentioned, there is approximately $24.5 billion left in the provider relief fund.
Additionally, $8.5 billion was allocated to rural providers with the passing of the American Rescue Act on March 11, 2021.
There has been a substantial reduction in resident and employee cases since the rollout with our current reporting as of last week, showing less than 550 cases, resident and employee, across less than 250 of our buildings, which low numbers have not been seen since April of last year.
The final project cost is expected to be approximately $310 million.
Lease-up momentum has been solid with 35 move-ins through April, the first full month of operations.
By example, our Maplewood portfolio, which is concentrated in the early affected Metro New York and Boston markets, saw meaningful census erosion early in the pandemic with second-quarter census hitting a low of 80.4% in early June.
That said, their portfolio occupancy level had returned to 85.6% in the month of November.
Including the land and CIP, at the end of the first quarter, Omega Senior housing portfolio totaled $2.2 billion of investment on our balance sheet.
This portfolio, excluding the 24 Brookdale properties, on a stand-alone basis had its trailing 12-month EBITDAR lease coverage fell 4 basis points to 1.08 times in the fourth quarter of 2020.
We invested $16.8 million in the first quarter in new construction and strategic reinvestment.
$9.4 million of this investment is predominantly related to our active construction projects.
The remaining $7.4 million of this investment was related to our ongoing portfolio capex reinvestment program.

Summary:
Our adjusted FFO of $0.85 per share, and our funds available for distribution of $0.81 per share allowed us to maintain our quarterly dividend of $0.67 per share.