The seven-month delay to allocate federal funds to combat Zika negatively affected research on other diseases such as Alzheimer's, diabetes and cancer in order to maintain funding levels for a Zika vaccine.
On Wednesday, Congress ended months of inaction with a vote in favor of allocating $1.1 billion toward supporting the country's response to the disease. In February, President Barack Obama asked for $1.9 billion.
“The effects of this delay in funding is probably going to be felt years down the road,” said Dr. Bruce Lee, an associate professor of International Health at the Johns Hopkins Bloomberg School of Public Health.
The package allocates $933 million toward the Zika response, which combined with money already transferred from an Ebola fund, bringing the total effort to $1.4 billion, according to a breakdown of the funding package by the Senate Appropriations Committee.
Nearly $400 million will go toward mosquito control and surveillance, while another $397 million will support development of a vaccine and the commercialization of diagnostic tests.
In a letter sent last month to Congress, HHS Secretary Sylvia Matthews Burwell said she was being forced to divert $34 million in funding devoted to research for Alzheimer's, diabetes and cancer to continue to develop a Zika vaccine.
Without such a move, Burwell estimated funding for Zika research would have been exhausted by the end of August.
“Reallocating NIH resources is not consistent with a strategy to provide maximum support to the important work that our nation's leading scientists are performing,” Burwell said.
Last month, the National Institutes of Health began testing a vaccine candidate, and Pennsylvania-based Inovio Pharmaceuticals announced the launch of a clinical vaccine trial in Puerto Rico, where nearly 20,000 cases have been reported as of Sept. 21.
“It may have somewhat been at the expense of other funded priorities that were deemed less important in the environment where they basically had limited funds,” said Dr. Amesh Adalja, a senior associate at the UPMC Center for Health Security.
Calls for Congress to act were at their peak in July, during the height of mosquito season. Lawmakers went on a seven-week recess without passing a funding bill. Over that time, the first reported cases of infection from local mosquitoes occurred in South Florida, prompting the Centers for Disease Control and Prevention to issue a first-ever travel alert for a part of the contiguous U.S.
Republicans and Democrats earlier this summer battled over objections to a GOP-led provision that would have restricted Planned Parenthood from receiving any funding.