Israeli researchers are checking corona vaccine against Omicron

Tests on the efficacy of inoculation are currently being conducted at the Sheba Medical Center.

 A photo illustration showing ampoules of Covid-19 vaccine for children at a Clallit vaccine center in Jerusalem on November 28, 2021. (photo credit: OLIVIER FITOUSSI/FLASH90)
A photo illustration showing ampoules of Covid-19 vaccine for children at a Clallit vaccine center in Jerusalem on November 28, 2021.
(photo credit: OLIVIER FITOUSSI/FLASH90)

Israeli researchers are conducting tests to understand more about the efficacy of the corona vaccines against the new Omicron variant and hope to have results in another few days

As of Monday, 21 Omicron cases had been identified in Israel, too small a sample to extract significant information from community infections. However, researchers are already working in the labs.

“The process takes between 10 and 20 days,” said Prof. Ella Mendelson, director of the Central Virology Laboratory at Sheba Medical Center at Tel Hashomer. “We are still working on the first phase of the experiment. Its goal is to grow the virus in the lab.”

Vaccine efficacy against infection can be examined in two ways: in the laboratory to see if antibodies found in the blood of vaccinated individuals inhibit the variant, or by collecting data from the field to show how many vaccinated individuals become infected compared with unvaccinated individuals.

Mendelson said that the virus is grown in tissue culture in a flask where it can remain alive. The flasks are then put into an incubator, where the virus can infect the cells and start to multiply within them.

 A CHILD takes a coronavirus test as part of a simulation presented by Sheba Medical Center for how pupils can return to study at the beginning of the new school year.  (credit: MIRIAM ALSTER / FLASH 90) A CHILD takes a coronavirus test as part of a simulation presented by Sheba Medical Center for how pupils can return to study at the beginning of the new school year. (credit: MIRIAM ALSTER / FLASH 90)

“This phase takes between five and 10 days,” she said. The virus has grown enough when the cells begin to die. At this point, we take out the material from a flask, and we spin it in a centrifuge so that all the cells go down to the bottom and all the fluids remain on the top. Then we need to perform a PCR test on the fluids to check the amount of virus and make sure that we have enough [virus] to go to the second step.”

To begin the second step, the virus is once again grown on a different type of tissue culture to measure it exactly. “By then, we can move on to the real experiment,” said Mendelson.

For this purpose, the scientists use patients’ serum extracted from their blood to check whether their antibodies prevent the virus from infecting the cells.

The serum can contain antibodies produced either by prior infection or as a result of vaccination. The researchers also dilute it to check how much concentration of antibodies is necessary in order for them to attack the virus.

“This way we will be able to see if the virus can escape antibodies produced by previous infection with other variants, like Alpha or Delta, or those produced by vaccination,” Mendelson said.

This experiment can offer indications about how effective antibodies are in preventing infection by Omicron, but does not offer insights about symptoms or severity of the disease if infection does occur – another important part of vaccine efficacy.

“This work does not tell you how a human body will react to the virus,” she said. “For this, we will need to look at data from the community.”

A Health Ministry representative said that as soon as the results of the research are ready, they will be shared with the public.

Such tests do not provide a complete answer to how effective a vaccine is in protecting an individual from the virus, because antibodies represent only one part of the immune system and its ability to respond to a pathogen. However, they are considered to offer an important indicator as to the potential response.

Earlier in the day, Health Ministry Director-General Prof. Nachman Ash said that he hoped that information on vaccine efficacy would be available in the next few days, both from laboratory tests and from the data arriving from the rest of the world.

Omicron has been described by experts as the most mutated variant so far with around 50 mutations, including a relevant number in the spike protein – the part that the virus uses to attack human cells as well as the element on which current vaccines focus.