Times are hard for vaccines candidates to succeed. Merck & Co's decision to discontinue its V590 and V5921 projects following disappointing early efficacy data on two potential Covid-19 vaccines shows that all developments will not get to the market eventually. Bad news for the "more than" 230 vaccines candidates identified by the World Health Organization so far, using an array of different techniques. With 7 vaccines approved by regulators for full or emergency use in at least one country, it is clear that the worldwide Covid-19 pandemic and its variants are far ahead of.

After Merck & Co (which said that it would focus on studying two possible treatments for the virus that had yet to be approved), others companies might soon be forced to follow suit being too late to the game. That may be the case with Sanofi and partner GlaxoSmithKline, but also Curevac as the company has already given up the US market, citing "market saturation". Early January though, it announced an agreement with Bayer to support the mRNA in two doses vaccine's development.

In spite of these mixed news, what are the most promising projects? Apart from Pfizer-BioNTech, Moderna or even AstraZeneca-Oxford University, which companies are still in the lead? Pharmanetwork tells you more.

Among the most advanced candidates, american Johnson & Johnson and Novavax seem to be well positioned with imminent data expected very soon. Johnson & Johnson's adenoviral vector-based project JNJ-78436735 is a one-dose regimen; the company has also started a pivotal study of a two-jab regimen. If the single-shot data from the phase 3 trials are positive, the company could seek US FDA approval.

In the case of Novavax, its recombinant protein candidate NVX-CoV2373 is close to yield pivotal data from two phase 3 trials ongoing in the S and Mexico and in the UK. Production ranges from 1 billion to 2 billion doses this year.

In Russia, the state-controlled Gamaleya Research Institute surprised the world last August being approved for limited use before phase 3 trials had started. With a 95 % efficacy rate according to interim analysis of trial results, its vaccine received an emergency use approval in Latin America, in Algeria and in Serbia. Russia anticipates demand of at least 2.4 billion doses.

In China, where the pandemic started one year ago, Sinopharm's two vaccines candidates have already been widely distributed even though trials are ongoing. The company develops its projects in partnership with the Wuhan Institute of Biological Products and the Beijing Institute of Biological Products. Both are inactivated virus in two doses. Another company, SinoVac, has launched phase 3 trials in China, Turkey and Brazil, with conflicting data on the efficacy rate.

Even India is running vaccine projects. Bharat Biotech was the first company to get approval for emergency use on January 3. Its vaccine candidate production could range 300 to 500 million doses in 2021.

Meanwhile, Moderna still races. The company confirmed on January 25 that its Covid-19 jab (mRNA-1273) still worked against the variant named 501.V2, which emerged in South Africa, and B.1.1.7, which was first discovered in the UK. But it warned that the neutralising antibody response to 501.V2 was sixfold lower than to the original variant. As a consequence, it will start phase 1 development of an emerging variant booster candidate, mRNA-1273.351, against the B.1.351 variant first identified in South Africa.