Researchers in the U.K. are beginning human trials to see if it’s possible to boost effectiveness of the COVID-19 vaccine by using one manufacturer’s initial dose and a booster shot from another drug company.

Such a procedure, called heterologous prime-boost vaccination, aims to see if the combo increases immune response to the virus.

According to The Wall Street Journal, mixing and matching vaccine doses isn’t a new strategy. Heterologous prime-boost vaccination has been successful against other infectious diseases such as malaria, Ebola, and tuberculosis. The technique has been used to enhance the immune response against certain cancers.

Experts say that by combining vaccines which have different mechanisms to attack the virus, it’s possible to bolster the reaction and dampen the risk of the body rejecting the second dose of the same vaccine. The Russian Sputnik V vaccine includes a different viral carrier in each of its two doses to ensure the immune system is not complacent about the second dose.

AstraZeneca announced it was testing its vaccine, which was developed in conjunction with the University of Oxford, with the Russian vaccine to gauge the efficacy of a one-two punch with different carriers.

The human trials now underway in Britain will evaluate the combination of Pfizer’s mRNA vaccine and the AstraZeneca jab that uses a modified chimpanzee virus as the delivery mechanism. Mary Ramsay, an epidemiologist and head of the Immunization, Hepatitis, and Blood Safety Department at Public Health England, said the success of this trial could help resolve bottlenecks in vaccine distribution.

“It really makes implementation more simple,” she said, according to the Journal. Researchers added that if the mix-and-match trials of the vaccines prove to be even more effective than giving the same drug twice, it may be a way to suppress the spread of the new variants of SARS-CoV-2 that are challenging the current vaccines.