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The subsequent crop of COVID-19 vaccine builders goes a extra conventional route

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Β© Reuters. FILE PHOTO: Small bottles labeled "Vaccine" stand near a medical syringe in front of the words "Coronavirus COVID-19" displayed in this image

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By Julie Steenhuysen and Caroline Copley

CHICAGO / BERLIN (Reuters) – The few drug manufacturers dominating the global race for coronavirus vaccines are pushing the boundaries of vaccine technology. The next crop in development features more conventional, time-tested designs.

The world will need several different vaccines to fight the COVID-19 pandemic, given the vast global needs, different impacts on different populations, and possible limits to effectiveness in the first harvest.

Many leading candidates currently in the final stages of testing are built on new, largely unproven technology platforms that will allow vaccines to be manufactured quickly. This includes that of Moderna Inc (O πŸ™‚ and Pfizer Inc (N πŸ™‚ with partner BioNTech SE (F πŸ™‚ and inactivated cold virus platforms used by Oxford University / AstraZeneca Plc (L :), Johnson & Johnson (N πŸ™‚ and CanSino Biologics (HK :), their vaccine has been approved for military use in China.

Merck & Co. (N πŸ™‚ started testing a COVID-19 vaccine in September based on a weakened measles virus, which releases genes from the new coronavirus into the body to stimulate an immune response to the coronavirus.

Of these, only the technology offered by J&J and CanSino, which uses cold viruses as vectors to deliver coronavirus genetic material, has ever made a licensed vaccine for Ebola.

The next group of candidates – with late-stage study results expected in the first half of 2021 – are heavily focused on approaches that have spawned successful vaccines.

Conventional methods involve the use of a killed or inactivated version of the pathogen that causes a disease that elicits an immune response, such as those used in the manufacture of vaccines against influenza, polio, and rabies.

Also more common are protein-based vaccines that use purified parts of the virus to trigger an immune response. Whooping cough or pertussis and shingles vaccines use this approach.

French drug maker Sanofi (PA πŸ™‚ is developing a protein-based COVID-19 vaccine that uses the same approach as its seasonal flu vaccine Flublok. Sanofi expects the final test phase to begin in early December. Approval is scheduled for the first half of 2021.

While Novavax Inc (O πŸ™‚ has not yet made an approved vaccine, uses similar technology for purified protein, and expects to start a late-stage U.S. study with 30,000 volunteers in late November.

"These are more traditional approaches so we can be more comfortable if we have a lot of experience with them," said Dr. Paul Offit, director of the Vaccination Education Center at Philadelphia Children's Hospital.

Offit also sees promise for some of the inactivated viral vaccines being developed by Chinese researchers, including Sinopharm's China National Biotec Group (CNBG), one of the few first culture developers using a traditional technique.

Other second wave developers are making vaccines based on virus-like particles (VLPs) that mimic the structure of the coronavirus but contain no genetic material.

VLP vaccines can be made in a variety of different cell types, including mammalian, bacterial, insect, yeast, and plant cells. This approach has been used to develop vaccines against hepatitis B and human papillomavirus.

Quebec's Medicago is testing a VLP COVID-19 vaccine grown in tobacco plants with support from tobacco company Philip Morris (N :).

Medicago has not yet made an approved vaccine, but has completed extensive testing of a seasonal flu vaccine using this approach. It plans to start mid-stage studies of its COVID-19 vaccine next month and produce up to 1 billion doses per year by 2023.

Others are looking for alternative delivery methods, such as the nasal spray vaccine, which is being developed by a team from Xiamen University, Hong Kong University, and the Beijing Wantai Biological Pharmacy Enterprise, and is based on a modified flu virus.

FUTURE CHALLENGES

The second crop, however, could struggle to complete large studies if current leaders cross the finish line with their vaccines in the coming months.

"If we receive a super vaccine from company x that is on the market in December, it will be difficult to attract participants for other studies," said Peter Kremsner from the University Hospital in TΓΌbingen.

"Then everyone will say, if the vaccine exists, I'll get this vaccine now. This will definitely be a recruitment problem," added Kremsner, who is the CureVac (O πŸ™‚ mRNA COVID-19 vaccine in early clinical trials Studies tests with support from the Bill & Melinda Gates Foundation.

On the other hand, it is easier and faster to prove effectiveness when the spread of the virus is widespread in the community, as it is again in the US, Europe and elsewhere. This is a potential benefit for companies starting large-scale vaccine trials in the near future.

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