When might we have vac­cine or a treat­ment?

Hun­dreds of vac­cines and treat­ments are in devel­op­ment

The Irish Times - - Home News - Kevin O’Sul­li­van

The re­mark­able global ef­fort to pro­duce a range of Covid-19 vac­cines in par­al­lel with de­vel­op­ing new treat­ments – many of which are adapt­ing proven med­i­ca­tions for other dis­eases – is gath­er­ing pace.

The scale of sci­en­tific en­deav­our is un­prece­dented, not just in terms of find­ing a new vac­cine, but in the level of co-op­er­a­tion be­tween sci­en­tists; in quickly shar­ing re­sults, data and crit­i­cal ge­netic de­tails; in­di­ca­tions of vari­a­tions in the form of what is known as SARS-CoV-2.

A rough as­sess­ment of tim­ings on po­ten­tial vac­cines would sug­gest early op­ti­mism needs to be tem­pered and early 2021 is the most likely time one will be­come avail­able - and only then in some coun­tries.

Should we plan for a vac­cine in 2021?

Trin­ity Col­lege Dublin im­mu­nol­o­gist Prof Luke O’Neill al­ways refers to a horse-rac­ing metaphor; you may be lead­ing the Grand Na­tional and have just one fence to clear, and fall at the last hur­dle.

The world has to face up to the fact that there may never be an ef­fec­tive vac­cine. But O’Neill is quick to add that the abil­ity to con­tain the novel virus through a com­bi­na­tion of ther­a­pies is very likely – as was the case with Aids. Like­wise, there are al­ready treat­ments emerg­ing that will act as a bridge to get­ting a vac­cine in place.

The one dis­cor­dant note un­der­min­ing this tremen­dous team play is wealthy coun­tries buy­ing up treat­ments, as seen with the US re­cently pur­chas­ing all the next three months’ pro­jected pro­duc­tion of the drug remde­sivir from US man­u­fac­turer Gilead: it cuts re­cov­ery times, though it is not yet clear if the drug im­proves sur­vival rates.

There re­mains the risk that more wealthy coun­tries aligned to pow­er­ful pharma com­pa­nies will do the same when a vac­cine emerges, and na­tional in­ter­ests will pre­vail over the need to give it to those re­quir­ing it most.

What is the emerg­ing pic­ture on lead­ing vac­cine can­di­dates?

There are more than 145 can­di­date vac­cines in devel­op­ment, with 17 in hu­man tri­als. Some have been shown to gen­er­ate a strong im­mune re­sponse in an­i­mals.

Those con­duct­ing vac­cine tri­als are “chas­ing the dis­ease around the world”, no­tably in Brazil and the US. Places where there are high lev­els of Covid-19 are the best to test ef­fi­cacy and safety.

The ex­tent of that re­search is likely to mean a range of vac­cines of dif­fer­ing type and ef­fec­tive­ness will emerge – the first to come on stream might not be the magic bul­let hoped for. But, given the whole world will need pro­tec­tion, a va­ri­ety of vac­cines from dif­fer­ent sources is not such a bad thing.

John­son & John­son has in­di­cated, for ex­am­ple, its vac­cine ap­peared so promis­ing in pre­clin­i­cal stud­ies they were able to push up the start of test­ing in healthy vol­un­teers to later this month.

The vac­cine uses a com­mon-cold virus to de­liver a coro­n­avirus anti­gen into cells to stim­u­late the im­mune sys­tem to fight off an in­fec­tion.

Other vac­cines con­tinue to make sig­nif­i­cant progress. An Ox­ford Univer­sity project is re­garded as of­fer­ing “the best chance of hav­ing some­thing pro­tec­tive against the virus as we go into win­ter”, MPs have been told.

It is be­ing tested in Brazil and South Africa, where the case num­bers are high. As­tra Zeneca, the com­pany part­ner­ing with Ox­ford, is to start a trial with 30,000 peo­ple in the US. Euro­pean coun­tries are lin­ing up be­hind the project

What about treat­ments?

The process of find­ing new treat­ments is quicker with lower reg­u­la­tory hur­dles to clear. How­ever, a widely avail­able med­i­ca­tion ap­proved for rou­tine use has not ma­te­ri­alised yet.

Nu­mer­ous tri­als are in progress with prompt en­dorse­ment of ef­fec­tive­ness or re­jec­tion. There has been too much haste on oc­ca­sion, as in the case of the anti-malaria drug hy­drox­y­chloro­quine, which con­tin­ues to pro­duce mixed re­sults.

Early in­di­ca­tions on dex­am­etha­sone – a cheap steroid – sug­gest it re­duced deaths by one-third in pa­tients who were on a ven­ti­la­tor. The drug, how­ever, looks to be ef­fec­tive only in pa­tients who are al­ready in a crit­i­cal state.

Remde­sivir re­duces the du­ra­tion of in­fec­tion in hos­pi­talised pa­tients but not mor­tal­ity. It does not come cheap, cost­ing $2,340 (¤2,080) per treat­ment in the US.

Other drugs such as da­clatasvir, used to treat Hepati­tis C; ima­tinib to treat leukaemia and favipi­ravir to treat in­fluenza are show­ing prom­ise. “Cock­tails” of these drugs could be de­ployed as they are no longer patented, mean­ing they would be eas­ily and cheaply made avail­able.

What pol­icy lessons can be learned?

For sci­en­tists and doc­tors who have had to wres­tle with the rapid spread of Covid-19 across the world, it is a game of con­stant catch-up.

The bot­tom line is a safe and ef­fec­tive vac­cine re­mains the best way to achieve herd im­mu­nity on a global scale. The lessons for fu­ture pre­pared­ness are clear.

Im­mu­nol­o­gist Sir John Bell of Ox­ford Univer­sity has crit­i­cised the lack of pan­demic plan­ning in the UK and par­tic­u­larly the ab­sence of man­u­fac­tur­ing ca­pac­ity for vac­cines. Virus out­breaks are, how­ever, a global prob­lem that will have to be ad­dressed through sus­tained fund­ing over many years.

The world must face the fact that there may never be an ef­fec­tive vac­cine

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