Summer may decide fate of lead shots in virus vaccine race

People on six continents alrey are getting jabs in arm as race for a COVID-19 vaccine enters a defining summer, with even bigger studies poised to prove if any shot really works -- and maybe offer a reality check.

Alrey British and Chinese researchers are chasing coronavirus beyond ir borders, testing potential vaccines in Brazil and United Arab Emirates because re are too few new infections at home to get clear answers.

U.S. is set to open largest trials -- 30,000 people to

Those likely will be divided among Americans and volunteers in or countries such as Brazil or South Africa, Dr. Anthony Fauci of National Institutes of Health told Associated Press.

While he’s optimistic, “we’ve been burned before,” Fauci cautioned.

Multiple successes, in multiple parts of world, are vital.

“This isn’t a race of who gets re first. This is, get as many approved, safe and effective vaccines as you possibly can," Fauci said.

Vaccine experts say it’s time to set public expectations. Many scientists don’t expect a coronavirus vaccine to be nearly as protective as measles shot.

If best COVID-19 vaccine is only 50% effective, "that’s still to me a great vaccine,” said Dr. Drew Weissman of University of Pennsylvania.

“We need to start having this conversation w,” so people won’t be surprised, he ded.

And for all government promises of stockpiling doses in hopes of starting vaccinations by year’s end, here’s catch: Even if a shot pans out -- and it’s one that your country stockpiled -- only some high-risk people, such as essential workers, go to front of a very long line.

“Will you and I get vaccinated this year? way,” said Duke University health ecomist David Ridley.

HOME STRETCH

Vaccines train body to rapidly recognize and fend off an inving germ. About 15 experimental COVID-19 vaccines are in various sts of human studies worldwide.

And while re’s guarantee any will pan out, moving three different kinds into final testing offers better odds -- especially since scientists don’t yet kw just how strong an immune reaction shots must spark to protect.

Measuring that with first proven vaccine will “really help us understand for all or vaccines in development, do y also have a chance?" said Oxford University le researcher Sarah Gilbert.

Only China is pushing out “inactivated” vaccines, me by growing new coronavirus and killing it. Vaccines by Sivac Biotech and SiPharm use that old-fashioned techlogy, which requires high-security labs to produce but is dependable, way polio shots and some flu vaccines are me.

Most or vaccines in pipeline target t whole germ but a key piece -- “spike” protein that studs surface of coronavirus and helps it inve human cells. Leing candidates use new techlogies that make shots faster to produce but haven’t yet been proven in people.

Oxford’s method: Genetically engineer a chimpanzee cold virus so it won’t spre but can carry gene for that spike protein into just eugh cells to trick immune system that an infection’s brewing.

Ar vaccine me by NIH and Moderna Inc. simply injects a piece of coronavirus genetic code that instructs body to produce harmless spike copies that immune system learns to recognize.

CHASING VIRUS

Researchers must test thousands of people t where COVID-19 is surging -- because n it’s too late -- but where it’s smoldering, Fauci said.

Only if virus starts spreing through a community several weeks after volunteers receive eir a vaccine or a dummy shot -- time eugh for immune system to rev up -- do scientists have best chance at comparing which group h more illness.

Lacking a crystal ball, NIH has vaccine testing networks in U.S., South America and South Africa on standby while finalizing decisions on summer tests.

“We’re going to be doing it in multiple sites with a degree of flexibility” so researchers can rapidly shift as virus moves, Fauci said. “thing is going to be easy.”

Oxford shot, with a 10,000-person study underway in England, alrey encountered that hurdle. Gilbert told a Parliament committee last week that re’s “little chance, frankly” of proving vaccine's effectiveness in Britain after infections plummeted with lockdown.

So her team looked abro. In dition to planned U.S.-run study,

With few new infections in China, Sivac next month will begin final tests in 9,000 Brazilian volunteers. And SiPharm just signed an agreement with United Arab Emirates; that study’s size isn’t clear.

EXPECT IMPERFECT PROTECTION

Animal research suggests COVID-19 vaccines could prevent serious disease but may t completely block infection. One study that dripped coronavirus into monkeys showed vaccinated animals avoided pneumonia but h some virus lurking in ir ses and throats. Wher it was eugh to spre to unvaccinated isn’t kwn.

Still, that would be a big win.

“My expectations have always been that we’ll get rid of symptomatic disease. From what we’ve seen of vaccines so far, that’s what y do,” said Penn's Weissman.

initial vaccines might be replaced with later, better arrivals, as historically happens in medicine, ted Duke’s Ridley.

And while shots in arm are fastest to make, those for respiratory diseases require virus-fighting antibodies to make ir way into lungs. Gilbert said Oxford eventually will explore nasal delivery.

WARNING AGAINST SHORTCUTS

Some U.S. lawmakers worry about pressure from Trump ministration to push out an unproven shot during fall election season.

“We want a vaccine, t a heline,” Sen. Jack Reed, a Democrat from Rhode Island, said at a recent Senate committee hearing.

Dr. Stephen Hahn, commissioner of Food and Drug ministration, pledged to a House committee last week that any decision would be based on science.

Different countries have different rules about when to release a vaccine. For U.S., Fauci insisted re will be safety shortcuts, a key reason NIH is investing in such huge studies.

Regardless of how and when a vaccine arrives,

Because each vaccine works differently, "which population group it will protect, we don’t kw yet,” said Dr. Mariangela Simao of World Health Organization, which is vising countries on how to choose.