[Jawahir Al-Naimi/Al Jazeera]

A skin patch is being trialled to administer the COVID-19 vaccine

By Dr Amir Khan-AL JAZEERA

According to a study in mice conducted by researchers at the University of Queensland and Griffith University in Australia, a vaccine administered via a skin patch could offer better protection against COVID-19 than those given via traditional needle injections.

The centimetre-wide (0.39 inch) patch contains 5,000 plastic spikes that are a quarter of a millimetre (0.009 inch) long. Each is coated with a dry version of the vaccine. Unlike the liquid form given in an injected vaccine, the dry version does not need to be stored at cold temperatures.

The researchers tested the skin patch with a COVID-19 vaccine candidate called HexaPro, which has been developed by researchers at the University of Texas at Austin. This vaccine is still undergoing clinical trials but has been shown to be more heat-stable than liquid vaccines. It remained stable for at least one month when stored on the patch at 25 degrees Celsius (77 Fahrenheit) and for one week when stored at 40C (104F). This makes it much more suitable for use in places without the cold storage facilities necessary for many liquid vaccines. It is also cheaper to manufacture than the existing approved vaccines.

According to the researchers, vaccines administered via a patch produced a better immune response because of the high density of immune cells on the surface of the skin. Mice treated with the patch developed more coronavirus antibodies than those injected with the vaccine and none showed any sign of sickness from the disease.

If these vaccines do eventually get the go-ahead, it will be music to the ears of those who are so needle-phobic that it has so far prevented them from taking up the COVID-19 vaccines.

Other advantages of this method of delivery include the ease of administering the vaccine, including the potential for self-delivery, or that it can be given by those who have no medical training. Unlike the Pfizer or AstraZeneca vaccines, the vaccine given as a patch does not have to be mixed or drawn up, and the fact that it can be stored at room temperature makes it easier to transport. The researchers also insist that it is painless.

The HexaPro is not the only vaccine being developed as a patch; Emergex, a UK company, has created a patch it says offers more long-lasting immunity than regular COVID-19 vaccinations. According to Robin Cohen, the chief commercial officer at Emergex Vaccines, their skin patch vaccine elicits high levels of T-cell immune cells that are important for long-lasting immunity and preventing transmission of the disease.

Emergex vaccines have been designed to be administered via the skin using microneedles and to be stable at ambient room temperature for more than three months, facilitating rapid and efficient distribution across the world and making administration of the vaccine more patient-friendly. The company is due to start Phase1 trials in 13 volunteers in Switzerland soon.

If these vaccines do eventually get the go-ahead, it will be music to the ears of those who are so needle-phobic that it has so far prevented them from taking up the COVID-19 vaccines.