Sinopharm reported its SARS-CoV-2 vaccine induced high levels of neutralizing antibodies in animal tests without causing any serious adverse events. The results of the preclinical trials were reported in the journal Cell. The vaccine, developed by a Sinopharm subsidiary, Beijing Institute of Biological Products, contains an inactivated form of the virus. Sinopharm is currently conducting China Phase I/II trials of BBIBP-CorV in three dosing strengths.

The Sinopharm researchers found that all three dosing levels produced neutralizing antibodies in mice that blocked the virus from infecting cells. However, a three-dose regimen produced higher levels of immunogenicity.

In rhesus macaques infected with SARS-CoV-2, all vaccine dosing levels lowered the viral load measured by throat swabs, but the animals that received the highest dose showed levels that were undetectable.

An inactivated vaccine like BBIBP-CorV is the time-honored approach for vaccine development. It is, however, delivered by an adenovirus, and many people who have previously been treated with an adenovirus-delivered vaccine have developed resistance to the delivery mechanism. For example, CanSino, a Tianjin vaccine company, reported that its SARS-CoV-2 vaccine discovered that about half the clinical trial subjects are resistant to the adenovirus delivery mechanism of its vaccine.

Inactivated vaccines also take more time to produce, an important consideration in a pandemic, and they require larger amounts of antigens than newer vaccine technologies.

According to market reports, there are more than 100 potential COVID-19 vaccines in development around the world. Moderna, CanSino, AstraZeneca, Pfizer, Merck, Sanofi and Johnson & Johnson are among the most prominent.

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Disclosure: none.