New Scientist - USA (2020-08-01)

10 | New Scientist | 1 August 2020

News Coronavirus

AMID rising global numbers of

daily coronavirus infections, a

fresh flush of vaccine trial results

is offering hope for the longer run.

There are more than

160 coronavirus vaccines in

development around the world.

About 140 of these are at the

preclinical stage, meaning they are

still being looked at in laboratories

and in animal tests. Another 25 are

already being tested in people.

The rate at which the tally has

risen to 160-plus is unusually

fast. “What is phenomenal is the

numbers changing over the past

few months. The amount of

research is incredible,” says Sheuli

Porkess at the Association of the

British Pharmaceutical Industry.

As the candidates advance,

the World Health Organization

(WHO) last month started to

convene a working group to

prioritise the most promising

vaccines. “Practical realities will

require a process that focuses

global efforts on a small handful

of candidates that may have the

highest impact,” the WHO said.

Four vaccines have made big

steps in development in the past

few weeks. Initial trials show

that they can trigger an immune

response and appear safe – but

it is too early to say if they will

protect against coronavirus and

whether they will work across

many different groups of people,

including older individuals and

those with chronic health issues.

On 20 July, a team led by

Sarah Gilbert at the University

of Oxford (see interview, page 8)

and pharmaceutical company

AstraZeneca showed that their

ChAdOx1 nCoV-19 vaccine

produced the desired immune

responses without showing

serious adverse reactions. That

was in a combined phase I/II trial

of 1077 volunteers (see “Trial

phases”, left). It is now being tested

in many thousands more people.

Six days earlier, US company

Moderna and the US National

Institute of Allergy and Infectious

Diseases revealed that 45 people

had received their mRNA-

vaccine and shown an antibody

response. On Monday, they began

a phase III trial intended to have

30,000 participants.

The other two most promising

candidates are from CanSino

Biologics in China, which

published encouraging phase II

trial results on the same day as

the Oxford team, and another

from German company BioNTech

with pharmaceutical giant Pfizer,

which published a promising

preliminary report on 14 July.

At this stage, we don’t know

which, if any, of the vaccines will

succeed. “The eyes of the world

are on these that are closest. But

without being pessimistic – I’m

being realistic – drug development

is a risky business,” says Porkess.

The much larger phase III trials

in coming months, involving

thousands of people, will give

a better idea of which vaccine

might be deployed first. “This

is the pointy end, this is when

you are getting into real-world

testing of a vaccine,” says Margaret

Harris at the WHO.

Any vaccines that are successful

in clinical trials will still need to be

manufactured at scale, which will

affect the time it takes to get a

vaccine for general use. “We are

seeing things happening at

unprecedented speeds. Maybe

something could [be licensed for

use] within 18 months from now,”

says Porkess. ❚

Vaccine trials

Adam Vaughan

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Vaccine effort yields a flurry

of positive trial results

139

Vaccines in preclinical trials,

not yet tested in humans

18

Vaccines in small-scale

phase I safety trials

11

Vaccines in large

phase II safety trials

5

Vaccines in large

phase III trials

25

Vaccines being tested in

humans, some of which are

in more than one trial phase

Phase I

A vaccine is given to a small

number of healthy people to

see whether it is safe to use

Phase II

A greater number and diversity

of people are tested, to see if it

triggers an immune response

Phase III

Involves hundreds or thousands

of people, including a control

group to see if the vaccine works

in the population at large

Combined phases

Because of the urgency of the

current pandemic, some phases

are happening in parallel

Trial phases

A volunteer in Seattle takes

part in a trial for a vaccine

developed by Moderna

Where are all

the vaccines?

Scores of vaccine candidates

are in development around

the world, but only a handful

have made it to the final

stages of testing, and none

has so far been approved for

general use.

SOURCE: WHO, 27 JULY 2020