Encouraging News From AstraZeneca Raises Hopes For A Covid-19 Vaccine
The AZD1222 vaccine showed promising results in phase II trials, but questions remain about efficacy and availability
On July 20th the UK pharmaceutical giant AstraZeneca released results of their phase I/II trial of the experimental coronavirus vaccine AZD1222. Hopes were raised when findings released in a press release showed that the vaccine stimulated immune response on par with convalescent plasma, with antibodies capable of neutralizing SARS-CoV-2. This news will carry them into the final phase of clinical trials set to begin later this summer to determine large scale efficacy of the vaccine.
The findings published in the Lancet show a strong immune response in participants who received the AZD1222 vaccine. This response involved both antibodies at levels on par with those who had been infected with Covid-19 as well as a strong cellular immune response. When challenged against the virus, antibodies from participants were capable of neutralizing the virus, signaling that this vaccine may be effective in protecting against Covid-19. The long-term protective of SARS-CoV-2 antibodies remains as researchers question whether the vaccine will produce a lasting immune response.
Furthermore, these clinical trials showed a strong cell based immune response — a characteristic found in patients exposed to SARS-CoV-2 but who never came down with a symptomatic disease. T-cell immunity appears to play a role in slowing the progression of symptomatic and severe Covid-19 in those infected.
The AZD1222 vaccine is an adenovirus vaccine that uses the inactivated viral vector to introduce coronavirus RNA that codes for the the spike protein, which acts as the primary immunogenic antigen on SARS-CoV-2. According to results from phase I/II trials, the virus will likely need two doses administered roughly a month apart to generate immunity.
Vice president for research and development, Mene Pangalos said of the results “…today’s data increases our confidence that the vaccine will work and allows us to continue our plans to manufacture the vaccine at scale for broad and equitable access around the world.”
AstraZeneca was the recipient of a $1.2 billion deal with the US government to secure a minimum of 300 million doses of the AZD1222 vaccine. This funding in conjunction with that of the UK helped fuel the development of the vaccine. Questions remain as to when the vaccine will be available, and which groups will be the first to receive it. It is likely that the first available doses will be made available to at-risk groups such as healthcare workers.
The cost of the vaccine remains yet another lingering question. Several pharmaceutical companies have indicated that they will likely price their vaccines beyond cost. This raises questions as to what degree the companies intend to profit from their vaccines. The cost of medication is already a prohibitive factor in access to care and a new Covid-19 vaccine is no exception. As the hurdle to develop a Covid-19 vaccine is crossed, there may remain an even greater challenge of equitably distributing the vaccine.
Phase III trials for the AZD1222 vaccine are set to start this summer in a cohort of 30,000 participants in the US alone. This phase of clinical trials will seek to determine efficacy of the vaccine at scale along with ongoing safety studies. Developers are still hopeful that early doses of the vaccine will be available by October 2020.