Coronavirus vaccine, eight racing candidates

These eight candidates for vaccines are conducting human trials in clinics in the United States, China, Britain and Germany. At least 94 others are behind them in different stages of development.

The Trump administration is putting pressure on hundreds of millions of doses of a vaccine available by the end of the year. However, experts say the unprecedented speed risks bypassing aspects of security and there is no guarantee that any of the vaccine will work.

The fact that we will not know the major issues about security and effectiveness if we plan to manage it quickly”, said Paul Offi, director of the Center for Vaccial Education at the Philadelphia Children's Hospital.

Three categories

Eight vaccine candidates rank in three categories.

A category may be called classical techniques: Promoting the patient's immune system to respond to the virus by injecting a killed version of it. Three separate groups of Chinese researchers are testing invasive virus vaccines.

A second method uses one virus to fight another.

Whether it causes COVID-19, Ebola, or common cold, a virus is essentially just an envelope containing instructions to reproduce the virus.

In this new vaccine strategy, scientists remove instructions from a virus and replace them with instructions to produce only a fraction of the coronary.

The injection of modified virus does not cause disease. The virus infects some of the patient's cells, but instead of copies of the infectious virus, these cells produce part of the coronary. The patient's immune system responds to the coronary protein so that it can fight against the true conqueror later.

Two separate groups in China and Britain are following this approach.

A third new strategy removes the mediator. Instead of giving instructions on a virus, researchers inject the genetic code of a part of the coronary directly to the patient in the form of DNA or RNA.

Two groups are working with RNA vaccines, one with DNA.

The newest methods are fast and flexible, according to Kimberly Taylor, leader of the vaccine development section and the National Institute of Allergy and Infectious Diseases.

“These vaccines are very good for pandemic cases, because they are usually too fast to try and, they can get very fast into clinical trials,” she said.

Good and Bad

Each technique has its own advantages and shortcomings.

We won't put all the eggs in a basket,” said the director at Emory University's Vaccines Centre, Walter Orenstein. Various “rups are seeking to see what will work and what cannot work. ”

The virus system killed is the most proven. But killing the virus can change his form. The immune system can respond to a virus killed differently from the true one.

The genetic change strategy of viruses is a new strategy and it is not clear how well the viruses of different carriers will function. In some cases, people may already have been exposed to the host virus, which would reduce its effectiveness.

DNA vaccines require special equipment.

It's not easy to use a needle and syringe. You must have a whole device,” says Taylor.

Never)known

Experts are concerned that the extremely tight deadline will not allow time for final answers if a vaccine is safe and effective.

The development of a vaccine usually lasts about 20 months. It is usually tested in tens of thousands of people before it is approved for a broader distribution because security issues may not be immediately obvious.

For example, in a clinical test of 35,000 patients, researchers found that a tropical fever vaccine did more harm than good for children under 9 who had never had a chance to get a vaccine. They developed worse cases of tropical fever than those not vaccinated before their first infection.

“You never know until there's been evidence in a large number of people,” said Offi. Then only then does it reveal what the truth is. ”

However, people can lower their standards for a coronary vaccine.

Because people are reasonably afraid of this virus, I think they're willing to accept a certain level of risk they would not normally accept,” addedof.

Since speed is of great importance, manufacturers must increase production before they know whether their vaccine works.

If you're a producer, what is your willingness to produce large amounts if your vaccine fails?

And how are we going to support the risk? Should there be any funds to say, if you develop a vaccine, we'll buy it even if we have to throw it down because the vaccine doesn't work or it's insecure? ”

The US government has signed agreements with two vaccine companies totalling nearly $1 billion, including production growth.

The results of the vaccine test are still months away for all candidates. (voa)