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.