出国访学需要了解的新冠肺炎疫苗知识(Covid-19 Vaccine)


  Covid-19 vaccine: “Hopefully next year we'll be living a normal life”

  The Pfizer/BioNTech vaccine - a collaboration between a US pharmaceutical giant and a German biotechnology company - offers up to 95% protection and is the first Covid-19 vaccine to be approved by US regulators.

  It is already being rolled out in the UK, while Canada also began its inoculation programme on Monday, with an initial 30,000 doses going to 14 sites across the country.

  US President-elect Joe Biden, who will be inaugurated as president on 20 January, has set a goal of 100 million Covid vaccinations in his first 100 days in office. That would represent roughly a third of the country’s total population.


  辉瑞/ BioNTech疫苗是由一家美国制药巨头与德国生物技术公司共同研发的新冠疫苗,有效性高达95%,现已被美国监管机构批准的首个新冠疫苗。


  美国总统当选人拜登(将于1月20日就任总统)公开申明在他上任的头100天,完成 1亿次新冠疫苗接种的目标,大约占美国总人口的三分之一。

  How Scientists Plan to Develop a Coronavirus Vaccine

  As the world continues to feel the impact of COVID-19, the biopharmaceutical industry is working around the clock to identify and develop safe and effective vaccines to prevent infection, while also researching and developing new ways to treat those infected with the virus.

  During this time, biopharmaceutical companies are working continuously with stakeholders across the R&D ecosystem to advance vaccine candidates as quickly and safely as possible.

  Step by step, here’s how scientists are aiming to develop a vaccine for COVID-19:




  Step 1: Identify And Sequence The Virus

  When evidence of a new virus is detected, scientists work to isolate and identify the specific virus in question. Once isolated, scientists can rapidly sequence the unique genetic code of the new virus, which provides information needed to help design diagnostic tests and potential vaccines and treatments.

  On January 10, 2020, Chinese health officials released the full genetic sequence of the novel coronavirus that can cause COVID-19, just a few weeks after the first case was discovered. The next day, researchers around the world started work on a vaccine.

  By comparison, it took several months after the discovery of SARS in 2002 to sequence the full SARS-CoV-1 genetic code with the tools available at that time. The much faster timeline in the case of COVID-19 illustrates recent improvements technologies that have dramatically shortened the time it takes to decode viruses and create a potential vaccine.





  Step 2: Determine The Target

  Vaccines work by imitating an infection to teach the immune system how to recognize, remember and target microbial invaders, like viruses and bacteria, without actually causing an infection. The process to determine how to best deliver a vaccine is complex as different approaches may work better for different pathogens.

  Historically, some vaccines, such as the measles vaccine, have used live but weakened versions of a pathogen, while others have used viral material that has been chemically inactivated or killed, which is the method used by the polio vaccine.

  Newer vaccines, such as the vaccine for hepatitis B, contain only a small part of a pathogen—usually a specific protein that the body can learn to recognize, known as an “antigen.” Given the pressing need for a safe and effective vaccine for the novel coronavirus, along with the volume of information that remains unknown about the disease, a wide range of approaches to vaccine development are being tested by biopharmaceutical researchers throughout the world to greatly improve the odds that one or more of these approaches will be successful.





  Step 3: Conduct Preclinical Trials

  Once researchers identify a vaccine delivery mechanism, cell cultures or animal models are used to test the vaccine’s potential safety and effectiveness. As of June 5, 2020, 129 vaccine candidates have entered preclinical testing.

  Notably, it’s common for vaccine candidates to fail during this part of the process, which is why we need as many shots on goal with as many viable candidates as possible.




  Step 4: Conduct Clinical Trials

  If a potential vaccine is successful in preclinical studies, scientists begin studying it in humans, which requires multiple types of clinical trials. Initial trials involve just a few dozen participants to provide evidence that a new vaccine is safe and to help researchers optimize dosing amounts. Demonstrating efficacy for vaccines presents unique challenges. Unlike most pivotal clinical trials, subjects in pivotal clinical trials for vaccines are otherwise healthy at the start of the clinical trial. Accordingly, demonstrating efficacy may require longer and larger clinical trials for vaccines than for other products.

  Additional trials examine the vaccine in hundreds to even a few thousand people to better understand how the immune system responds to a vaccine, whether it is effective and durable at producing immunity, and to further understand the vaccine’s safety profile. Depending on the vaccine and disease under study, thousands or even tens of thousands of participants may participate to increase understanding of a vaccine’s safety profile. As of June 5, 2020, ten coronavirus vaccine candidates have entered initial clinical trials.




  Step 5: Obtain Regulatory Approval

  By this point, the majority of vaccine candidates will have failed, underscoring the substantial risks and complexities involved. However, if a vaccine successfully makes it through clinical trial phases, researchers can apply for approval from the U.S. Food and Drug Administration (FDA). Applications for approval must meet FDA’s robust standards for safety, purity and potency to obtain approval, and include data generated pre-clinical testing and clinical trials, in addition to significant information on the manufacturing process.



  Step 6: Manufacturing And Distribution

  While the vaccine is going through clinical studies, biopharmaceutical researchers are also developing the manufacturing methods that will be used if the new vaccine is successful. For some types of vaccines used in large populations, these methods then undergo massive scale up to enable the manufacture of what can be many millions of doses. This is an enormous undertaking, as the transition from laboratory to manufacturing facility is incredibly complex and must ensure consistency in the vaccine composition and safety and efficacy profiles. As developing the manufacturing strategy can be a multi-year process, biopharmaceutical companies are already seeking to expand their manufacturing capacity. Companies are also initiating manufacturing capabilities at risk, well before a COVID-19 vaccine receives regulatory approval, to speed the production process when a vaccine is ready.

  Safely delivering a vaccine to patients around the world is an equally challenging undertaking, especially in less developed regions, as vaccines often require special handling, such as temperature control, during distribution. Biopharmaceutical companies are working closely with local governments and NGO partners to lay the groundwork for potential distribution at global scale.