The World Health Organization (WHO) warned Tuesday that there could be a shortage of vaccine syringes in 2022.

WHO expert Lisa Hedman said at a United Nations briefing that there have been 6.8 billion coronavirus vaccine doses administered, exceeding the total manufacturing capacity last year of 6 billion vaccine syringes, Reuters reported.

If manufacturing priorities aren’t changed, the world could see a shortage of 2 billion vaccine syringes in 2022.

“We could have a global shortage of immunization syringes that could in turn lead to serious problems such as slowing down immunization efforts as well as safety concerns,” Hedman said. 

“If we shift capacity from one type of syringe to another or attempt to expand capacity for specialized immunization syringes, it takes time and investment,” she added.

A shortage of syringes could lead to delays in routine vaccinations for children and other procedures, according to Reuters.

A shortage could also cause countries, particularly poorer countries, to unsafely reuse syringes, Hedman said.

The comments from the WHO expert comes as Europe is seeing a fourth wave of coronavirus cases.

WHO Regional Director for Europe Hans Kluge said the U.S. needs to take lessons from Europe’s fourth wave and implement coronavirus restrictions if the country begins to see a spike in cases.