The UAE — the most-vaccinated country in the world against Covid-19 — has approved another vaccine from China’s Sinopharm, to be used as a booster.
As reported in The National, the Ministry of Health and Prevention gave emergency approval this week for the recombinant protein-based vaccine before a roll-out set to begin next month.
State news agency Wam said that clinical trials in the Emirates showed the vaccine stimulated an immune response and did not result in side effects.
Among those involved in the trials were people who had previously received two doses of the Sinopharm inactivated vaccine, which has been widely used in the Emirates.
Here we take a look at the new Sinopharm shot.
What is a recombinant protein-based vaccine?
The word recombinant refers to the fact that genetic engineering has been used to produce the new Sinopharm vaccine.
Typically this involves genetic material from the pathogen being inserted into the genetic material of another organism, such as a yeast or a bacterium.
This causes the genetically engineered organism to produce, in this case, coronavirus proteins, which are extracted and purified, and included as part of the active ingredient of the vaccine.
When the vaccine is injected, the immune system recognises the coronavirus proteins -which are antigens — as “foreign” and responds by producing antibodies and other substances to use against them.
If the vaccine recipient is subsequently infected with the coronavirus, the earlier immune response to the vaccine means the immune system is prepared and should be better able to mount a defence against the pathogen.
Are recombinant protein-based vaccines new?
Unlike messenger RNA (mRNA) vaccines, such as the Moderna and Pfizer-BioNTech shots, recombinant protein-based vaccines were already being given to people before the coronavirus emerged.
The first vaccine based on recombinant DNA methods was one against Hepatitis B, that was approved by the US Food and Drug Administration in 1986.
For this vaccine, the antigen is produced by yeast cells that have had genes for the Hepatitis B surface antigen (HbsAg) inserted into their genetic material.
Some influenza (flu) vaccines are also produced using recombinant technology.
In this case, “host” cells produce haemagglutinin, an influenza surface protein.
There are other, older forms of technology used to produce vaccines. Inactivated vaccines, for example, have been used for more than a century.
These are often created by producing large numbers of virus particles before they are inactivated with chemicals, heat or radiation. The vaccine may contain the whole virus or just components of it.
How useful are recombinant protein-based vaccines?
Recombinant protein-based vaccines have been “extremely useful and extremely innovative”, according to Prof John Oxford, emeritus professor of virology at Queen Mary University of London and co-author of the textbook Human Virology.
“I’ve got nothing but admiration for the whole technology,” he said.
“I’ve got respect for Sinopharm and the other companies in China. They’re well established.”
He added that it was good that vaccines based on several types of technology — including mRNA vaccines, inactivated vaccines and recombinant protein-based vaccines, among others — had been produced to combat Covid-19.
“We don’t know all the ins and outs of these different vaccines against Covid,” he said.
“Some may produce a quick immune response, some a slow immune response.
“Some [may produce a] very broad [response], including T cells [a type of immune cell] as well as B cells [which produce antibodies], others a slow but longer-lived response. There are so many variations on the theme. Until the playing field levels, we will not be able to see which is best.”
What other Covid-19 vaccines has Sinopharm produced?
Sinopharm, the trading name of China National Pharmaceutical Group Corporation (CNPGC), has been one of the key producers of Covid-19 vaccines.
It has two inactivated Covid-19 vaccines, one of which, BBIBP-CorV (sometimes written simply as BIBP), was assessed during clinical trials in the UAE and other countries.
With this vaccine, large numbers of coronavirus particles are produced using vero cells, a type of lab-grown cell line, before the virus particles are rendered harmless or inactivated by chemical treatment.
Many people in the UAE who received this vaccine in the UAE were subsequently given a dose of the Pfizer-BioNTech mRNA vaccine as a booster.
In April media reported that China National Biotec Group Company, a Sinopharm subsidiary, had received approval to begin human trials of its protein-based coronavirus vaccine.
Five months later, in September, Sinopharm unveiled four “second-generation” Covid-19 vaccines designed to be more effective against the Beta and Delta coronavirus variants.
These four vaccines were of three types: inactivated virus, mRNA and recombinant protein-based, the last of which is the technology behind the vaccine being rolled out in the UAE.
Where will the new vaccine be made?
As reported in The National, the new Sinopharm vaccine, which will be used from January 2022, is being produced by Hayat Biotech.
Hayat Biotech — Hayat is the Arabic word for life — is a joint venture between Sinopharm and G42, an Abu Dhabi-based technology company.