SOURCE: CNN
By Eliz­a­beth Co­hen, CNN Se­nior Med­ical Cor­re­spon­dent

(CNN) — The Mod­er­na vac­cine is 94.5% ef­fec­tive against coro­n­avirus, ac­cord­ing to ear­ly da­ta re­leased Mon­day by the com­pa­ny, mak­ing it the sec­ond vac­cine in the Unit­ed States to have a stun­ning­ly high suc­cess rate.

"These are ob­vi­ous­ly very ex­cit­ing re­sults," said Dr. An­tho­ny Fau­ci, the na­tion's top in­fec­tious dis­ease doc­tor. "It's just as good as it gets — 94.5% is tru­ly out­stand­ing."

Mod­er­na heard its re­sults on a call Sun­day af­ter­noon with mem­bers of the Da­ta Safe­ty and Mon­i­tor­ing Board, an in­de­pen­dent pan­el an­a­lyz­ing Mod­er­na's clin­i­cal tri­al da­ta.

"It was one of the great­est mo­ments in my life and my ca­reer. It is ab­solute­ly amaz­ing to be able to de­vel­op this vac­cine and see the abil­i­ty to pre­vent symp­to­matic dis­ease with such high ef­fi­ca­cy," said Dr. Tal Za­cks, Mod­er­na's chief med­ical of­fi­cer.

Vac­ci­na­tions could be­gin in the sec­ond half of De­cem­ber, Fau­ci said. Vac­ci­na­tions are ex­pect­ed to be­gin with high-risk groups and to be avail­able for the rest of the pop­u­la­tion next spring.

Un­ex­pect­ed­ly high ef­fi­ca­cy rates

Last week, Pfiz­er an­nounced that ear­ly da­ta show its vac­cine is more than 90% ef­fec­tive against the dis­ease.

In Mod­er­na's tri­al, 15,000 study par­tic­i­pants were giv­en a place­bo, which is a shot of saline that has no ef­fect. Over sev­er­al months, 90 of them de­vel­oped Covid-19, with 11 de­vel­op­ing se­vere forms of the dis­ease.

An­oth­er 15,000 par­tic­i­pants were giv­en the vac­cine, and on­ly five of them de­vel­oped Covid-19. None of the five be­came se­vere­ly ill.

The com­pa­ny says its vac­cine did not have any se­ri­ous side ef­fects. A small per­cent­age of those who re­ceived it ex­pe­ri­enced symp­toms such as body aches and headaches.

Mod­er­na plans to ap­ply to the US Food and Drug Ad­min­is­tra­tion for au­tho­riza­tion of its vac­cine soon af­ter it ac­cu­mu­lates more safe­ty da­ta lat­er this month.

Fau­ci says he ex­pects the first Covid-19 vac­ci­na­tions to be­gin "to­wards the lat­ter part of De­cem­ber, rather than the ear­ly part of De­cem­ber."

Ini­tial­ly, there won't be enough vac­cine for every­one. The high­est pri­or­i­ty groups, which in­clude health care work­ers, the el­der­ly, and peo­ple with un­der­ly­ing med­ical con­di­tions, will get the vac­cine first.

"I think that every­body else will start to get vac­ci­nat­ed to­wards the end of April," Fau­ci said. "And that will go in­to May, June, Ju­ly. It will take a cou­ple of months to do."

A new vac­cine tech­nol­o­gy

Pfiz­er's and Mod­er­na's vac­cines have sim­i­lar re­sults be­cause they use the same tech­nique to ac­ti­vate the body's im­mune sys­tem.

The vac­cines de­liv­er mes­sen­ger RNA, or mR­NA, which is a ge­net­ic recipe for mak­ing the spikes that sit atop the coro­n­avirus. Once in­ject­ed, the body's im­mune sys­tem makes an­ti­bod­ies to the spikes. If a vac­ci­nat­ed per­son is lat­er ex­posed to the coro­n­avirus, those an­ti­bod­ies should stand at the ready to at­tack the virus.

No vac­cine cur­rent­ly on the mar­ket us­es mR­NA.

"There has al­ways been skep­ti­cism about mR­NA -- it's brand new and would it work?" Fau­ci said. "What we saw in the tri­als is there was no re­al safe­ty con­cern, and the ef­fi­ca­cy is quite im­pres­sive. We saw near­ly iden­ti­cal re­sults [with Pfiz­er and Mod­er­na] and it al­most re­al­ly val­i­dates the mR­NA plat­form."

Re­search on mR­NA be­gan many years be­fore the cur­rent pan­dem­ic. Fau­ci's agency, the Na­tion­al In­sti­tute of Al­ler­gy and In­fec­tious Dis­eases, has col­lab­o­rat­ed with Mod­er­na on the de­vel­op­ment of its vac­cine.

Both vac­cines are giv­en in two dos­es sev­er­al weeks apart.

Prac­ti­cal ad­van­tages of Mod­er­na's vac­cine

While the two vac­cines ap­pear to have very sim­i­lar safe­ty and ef­fi­ca­cy pro­files, Mod­er­na's vac­cine has a sig­nif­i­cant prac­ti­cal ad­van­tage over Pfiz­er's.

Pfiz­er's vac­cine has to be kept at mi­nus 75 de­grees Cel­sius. No oth­er vac­cine in the US needs to be kept that cold, and doc­tors' of­fices and phar­ma­cies do not have freez­ers that go that low.

Mod­er­na's vac­cine can be kept at mi­nus 20 de­grees Cel­sius. Oth­er vac­cines, such as the one against chick­en­pox, need to be kept at that tem­per­a­ture.

That means Mod­er­na's vac­cine can be kept in "a read­i­ly avail­able freez­er that is avail­able in most doc­tors' of­fices and phar­ma­cies," Za­cks said. "We lever­age in­fra­struc­ture that al­ready ex­ists for oth­er mar­ket­ed vac­cines."

An­oth­er ad­van­tage of Mod­er­na's vac­cine is that it can be kept for 30 days in the re­frig­er­a­tor, the com­pa­ny an­nounced Mon­day. Pfiz­er's vac­cine can last on­ly five days in the re­frig­er­a­tor.

*****

"This is re­al­ly a his­toric day," Health sec­re­tary says af­ter Mod­er­na an­nounces vac­cine re­sults

From CNN Health’s Nao­mi Thomas

Alex Azar, US Health and Human Services secretary. (Image courtesy U.S. Department of Health & Human Services)

Alex Azar, US Health and Hu­man Ser­vices sec­re­tary, praised the Mod­er­na coro­n­avirus vac­cine tri­al news this morn­ing on Good Morn­ing Amer­i­ca.

“Here we are, 10 months from the date when this virus hit out shores and we’ve got a sec­ond 90% plus ef­fec­tive vac­cine for the Amer­i­can peo­ple. This is re­al­ly a his­toric day,” he told George Stephanopou­los on Mon­day.

Azar said that be­cause the Mod­er­na and Pfiz­er vac­cines are al­ready be­ing pro­duced, they hope to have enough by the end of De­cem­ber to vac­ci­nate 20 mil­lion of the Unit­ed States’ most vul­ner­a­ble cit­i­zens.

When asked by Stephanopou­los about who would get the vac­cine first, Azar said “we’re go­ing to fol­low the guid­ance. Once the full da­ta pack­age is in, then we’re go­ing to fol­low the guid­ance of CDC.” 

“It’ll be wher­ev­er it’s go­ing to add the most val­ue ac­cord­ing to the da­ta and the sci­ence and the rec­om­men­da­tions of our ex­perts,” he said.