In the race to bring to market a vaccine against Covid-19, drug companies develop various strategies and focus on specific technologies. According to the World Health Organization, 23 coronavirus vaccines were being evaluated in clinical trials around the world at the end of July. Moreover, more than 100 projects were in earlier stages of development.

- mRNA-based vaccines
mRNA enables protein synthesis in the human body, carrying the genetic code required for cells to manufacture and express proteins. By using mRNA technology in vaccines and medicines, specific proteins (called antigens) can be produced by the body's own cells. They enable the human immune system to prevent or fight disease. GSK, Moderna or Pfizer bet on this technology to develop a vaccine.

July 20, GSK announced a collaboration agreement with german leader CureVac for the research, development, manufacturing and commercialisation of up to five messenger RNA (mRNA)-based vaccines and monoclonal antibodies (mAbs) to eliminate infectious disease pathogens. GSK will invest up to €150 million to acquire a 10 % stake in CureVac that had once attracted the White House and president Donald Trump. The British drugmaker will also make an upfront cash payment of €120 million and a one-time reimbursable payment of €30 million for manufacturing capacity reservation. CureVac will also be eligible to receive development and regulatory milestone payments of up to €320 million, commercial milestone payments of up to €380 million and tiered royalties on product sales. CureVac will be responsible for the preclinical- and clinical-development through Phase 1 trials of these projects, after which GSK will be responsible for further development and commercialisation. The british drugmaker is also working on a €550 million deal with Sanofi to supply the UK government with 60 million doses of their coronavirus vaccine. According to the deal, GlaxoSmithKline would supply the adjuvant, while Sanofi would provide the antigen.

July 1, Pfizer and german biotech BioNTech announced preliminary data from the most advanced of four investigational vaccine candidates from their BNT162mRNA-based vaccine program, Project Lightspeed, against Covid-19. Positive early results were released in two ongoing Phase I/II studies in the US and in Germany. A Phase II/III trial with 30,000 participants is due to start this month if the companies receive regulatory approval. Pfizer and BioNTech want to file their vaccine candidate by December. The companies expect to manufacture up to 100 million doses by the end of 2020 and potentially more than 1.2 billion by the end of 2021. According to Pfizer CEO Albert Bourla, the company has a budget of € 2 billion.

In May, the third company working on mRNA-based vaccines, Moderna, reported preliminary data from a Phase I trial on its two-dose vaccine mRNA-1273. Mid-July, it released detailed results from this trial in the NEJM, showing its experimental coronavirus vaccine induced anti-SARS-CoV-2 immune responses in all 45 study participants. But the most important question for the programme- the durability of any immuno-protective effects- could not be assessed in the Phase I results, given that reporting was limited to 57 days following administration. In a Phase II study, 300 patients have been enrolled. Its late-stage trial was delayed in July, but the company confirmed it still planned to enroll 30,000 people in the United States in a Phase III trial starting on July 27. Analysts forecast sales of more than $5 billion a year for the vaccine-candidate.

- DNA Vaccines
DNA vaccines are similar to the mRNA offerings in that they depend on a patient's own cells to create the antigen protein encoded by the mRNA. DNA vaccines are more stable and less immunogenic. Several drugmakers work on this technology, like AstraZeneca.

On July 20, AstraZeneca reported that its Oxford University-partnered vaccine AZD1222 against COVID-19 increased levels of both neutralising antibodies and T-cells that target the SARS-CoV-2 virus in a Phase I/II study. According to the World Health Organization, the drug is considered as the most advanced vaccine candidate so far. The results published in The Lancet showed it covered both bases (it produced T-cell and an antibody response). Oxford University has already started recruiting for Phase II/III testing of AZD1222 in around 10,000 adults.

End of June, Inovio Pharmaceuticals reported interim Phase I data indicating that its experimental vaccine candidate INO-4800 was "deemed safe and well-tolerated," through eight weeks. However, no data about participants' antibody response were disclosed. Questions were raised in regards to the strength and duration of neutralising antibodies and T-cell responses. The Phase I trial began in April and recruited 40 healthy adults volunteers in the United States. End of July the company still planned a Phase II/III efficacy study this summer in the United States.

Big Pharma also dominates the global vaccine market with more "traditional" R& D projects. End of July, Johnson & Johnson disclosed that it hoped to begin a late-stage study of its Covid-19 vaccine candidate Ad26.COV2-S in late September, ahead of its previous schedule. The company also planned to start a Phase I trial of the recombinant vaccine in Belgium, enrolling more than 1 000 participants, primarily between the ages of 18 and 55 years. According to Johnson & Johnson, "initial data on the Phase I will then become the basis for a Phase III study, that will start mid-to-end September." The drugmaker was also planning a Phase II trial in the Netherlands, Spain and Germany. The company has previously said it was committed to supplying more than 1 billion doses of the vaccine worldwide in 2021.

Last but not least, Merck & Co intends to develop two vaccines against SARS-CoV-2 and to license an oral antiviral candidate. Under the first deal, Merck agreed to acquire Themis Bioscience and its experimental Covid-19 vaccine candidate, in preclinical development with clinical studies planned to start later this year. Under a separate collaboration with IAVI, it also expects to advance a second preclinical vaccine against SARS-CoV-2 into clinical trials later this year, based on its Ebola Zaire virus vaccine, Ervebo.