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Coronavirus vaccine: This week's updates from Moderna, Pfizer and more

Experts caution that even promising early results don’t guarantee that vaccines will be widely available anytime soon.
Cambridge Biotech Moderna Leads in Race For Coronavirus Vaccine
A scientist works in the lab at Moderna in Cambridge, Mass. on Feb. 28, 2020.David L. Ryan / Boston Globe via Getty Images

Work on a potential coronavirus vaccine is proceeding at breakneck pace around the world, with more than 100 projects in motion, yet even the best predictions put an effective vaccine at least nine months away.

And experts are cautioning that even promising early results don’t guarantee that vaccines will be widely available anytime soon, because clinical trials are done in phases and require observing participants over time to assess how they respond to the doses.

The first week of May included several notable announcements about efforts to create a coronavirus vaccine. In the U.S., the Massachusetts-based biotech company Moderna announced Thursday that their coronavirus vaccine candidate received approval from the Food and Drug Administration to proceed with a second round of clinical trials. And scientists at the pharmaceutical company Pfizer are working on a new vaccine that they say could be available by September.

In the U.K., scientists at the University of Oxford made waves recently when researchers there said that they may be able to evaluate the effectiveness of their candidate this summer, and the vaccine could subsequently be available by September.

Here's a roundup of the most notable vaccine news of the week.

Moderna vaccine moves to phase two of trials to test side effects and efficacy

Moderna is moving forward with a second phase of clinical trials after receiving clearance from the FDA.

Like Pfizer, Moderna’s vaccine candidate is based on specially designed messenger RNA. The company’s first phase of human clinical trials, involving more than 100 healthy volunteers, was conducted in March.

If the second round of trials is successful, Moderna said it anticipates beginning the third phase of clinical trials, which is designed to demonstrate that the vaccine is effective in different populations, in early summer.

Moderna also announced a partnership with Lonza Ltd., a biotechnology firm based in Basel, Switzerland, to produce up to 1 billion doses of the potential vaccine each year.

“We are accelerating manufacturing scale-up and our partnership with Lonza puts us in a position to make and distribute as many vaccine doses of mRNA-1273 as possible, should it prove to be safe and effective,” Stéphane Bancel, Moderna’s chief executive, said in a statement.

University of Oxford could be able to evaluate its vaccine by June

A vaccine candidate developed by scientists at the University of Oxford is one of eight being tested on humans in clinical trials.

In a May 3 appearance on NBC’s “Meet the Press,” Sir John Bell, the Regius professor of medicine at the University of Oxford, said the prospects so far are “pretty good,” and added that Oxford scientists will likely be able to evaluate the vaccine candidate’s efficacy by June.

The Oxford vaccine includes genetic instructions for the spiked-shaped protein on the surface of the virus that helps it bind to a host cell. The basic idea is that if the vaccine can instruct human cells to produce the protein and a person’s immune system can learn to recognize it, the body’s own defense systems can better protect against infection from the virus.

In tests done at the National Institute of Health’s Rocky Mountain Laboratory in Montana, a single dose of the Oxford vaccine was effective at protecting rhesus macaque monkeys from developing COVID-19, the disease caused by the coronavirus — even after the monkeys were exposed to large quantities of the virus.

In human clinical trials, the scientists are aiming to test the potential vaccine on around 6,000 volunteers, who will be monitored over time.

Rhesus macaques and humans are thought to have similar immune systems, but encouraging results in animal tests doesn’t necessarily mean human trials will yield the same results.

Pfizer 'messenger RNA' clinical trial in U.S. begins

Scientists at Pfizer and a German pharmaceutical company, BioNTech, developed a potential coronavirus vaccine that began human clinical trials in the U.S. this week. The tests are being done on up to 360 healthy volunteers in the first phase, the company said in a statement.

Phase one clinical trials are used to test the safety of the vaccine, but do not look at how well it works. Phase two trials evaluate the drug’s effectiveness and look for any side effects.

The Pfizer and BioNTech vaccine candidate contains genetic material known as messenger RNA that has been reprogrammed to instruct human cells to make so-called spike proteins associated with the coronavirus. The vaccine is designed to teach a person’s immune system to produce the antibodies necessary to ward off the viral infection.

Several other biotech companies and pharmaceutical firms are working on similar projects based on messenger RNA, but Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children's Hospital and dean of the National School of Tropical Medicine at the Baylor College of Medicine in Houston, previously told NBC News that these types of vaccine candidates have worked in laboratories but not necessarily produced comparable immune responses in humans.

Resource constraints

Even as vaccine development is forging ahead, some experts are warning that resource shortages could pose problems down the line.

Just as supply chain issues prevented many states from administering enough diagnostic tests for the coronavirus, the same resource constraints could affect the manufacturing and distribution of vaccines.

“We’re thinking about the vaccine, but what if the vials it is stored in, or rubber stoppers in the vial or the plungers in the syringes become the constraint?” Prashant Yadav, a senior fellow at the Center for Global Development in Washington, told The New York Times.

The World Health Organization has also underscored the need to ensure that coronavirus vaccines are shared equitably with all countries once they are available. There are some fears that distribution of any drugs and vaccines to fight COVID-19 may be rolled out unevenly between wealthier and poorer nations.