First identified in Wuhan, China in late 2019, and declared a global pandemic in March 2020, the COVID-19 has become a pressing burden. As the pandemic continues to unfold, there has been an extensive impact on global health with substantial mortality records and a negative influence on the global economy.
In the face of the global spread of the virus, although large sections of the population in many countries have escaped infections, they remain non-immune to the SARS-CoV-2 virus. Researchers underline that vaccines can play a significant role to increase herd immunity within the population. Vaccines are vital because of their potential to reduce the devastating effects of the pandemic. Covid-19 vaccination will be efficient because it will not only help to protect the individual receiving the vaccine but also prevent the spread of disease to others. Therefore, the demand that the entire population should be vaccinated against the SARS-CoV-2 virus has drastically increased.
In response, swift global efforts to develop and test a variety of vaccines against SARS-CoV-2 have resulted in an unprecedented number of candidate vaccines going through clinical trial since mid-2020.
What’s going on in Research?
Presently, immense scientific collaborations and financial investments have drastically accelerated the overall research and development process for safe and effective COVID-19 vaccines. As of January 13, 2021, the International Clinical Trials Registry Platform (ICTRP) recorded more than 147 randomised clinical trials (RCTs) and 34 non-randomized studies that are under development on more than 10 different types of vaccines. Of all these studies, 93 are recruiting patients diagnosed with the COVID-19 virus. Approximately 154 of these studies are in the pre-clinical trials stage; 21 are in phase 1 of ‘small-scale safety trials’; 12 in the ‘expanded safety trials’; and 11 in phase 3 of ‘wider testing and effectiveness assessment’. Several of these trials have communicated good immunogenicity and safety findings, and they include Oxford, Moderna and Pfizer/BioNTech vaccines that have already been approved and are being rolled out in selected countries such as; the US, Israel, UK, China, the EU, Germany, Turkey, Canada, Japan, Peru, and Mexico.
The Oxford vaccine (ChAdOx1 nCoV-19)
In the United Kingdom, the Medicines and Healthcare products Regulatory Agency (MHRA) in December 2020 approved the Oxford vaccine (ChAdOx1 nCoV-19) with distribution currently underway since 5 January 2021. So far, the vaccine is approved for emergency use in the UK, India, Argentina, Morocco, and El Salvador.
The vaccine is made from a weakened adenovirus (common cold virus) that has been re-engineered to make it unable to replicate in humans. RCTs conducted on the vaccine across the UK, Brazil, and South Africa indicated that the vaccine is effective against symptomatic Covid-19 patients. The findings showed that the vaccine reduced the development of Covid-19 symptoms in up to 70% of the participants. Further research is currently underway to optimize performance by up to 90%. Presently, the Oxford vaccine is administered in 2 doses, with priority given to at-risk groups who receive the first dose at the outset. The second dose is vital for long term protection and is given 12 weeks after the first dose. Deployment has been rapid as the vaccine is stable and can easily be stored and transported to different health care setting.
Apart from AstraZeneca, the major funding agencies for the research and development of the Oxford vaccine include National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, the Lemann Foundation, and the Bill & Melinda Gates Foundation among others.
Moderna Vaccine (mRNA-1273)
The Moderna Vaccine (mRNA-1273) on the other hand is an mRNA vaccine developed from a fragment of the SARS-CoV-2 virus genetic code. The RNA works by making part of the virus in the body. Once the body recognizes the virus as foreign, it attacks it. Based on clinical efficacy trials, the Moderna vaccine is showed to protect up to 94.1% of confirmed Covid-19 patients who have received the complete two doses. The two doses of Moderna are spaced four weeks apart. The United States is expecting up to 20 million doses of Moderna, while the UK has an order of 5 million doses expected to start in spring, 2020 and to immunize up to 2.5 million people.
Storage appears to be easy as it remains stable at minus 20C and can stay active for six months, and in a standard refrigerator for close to a month.
The Pfizer-BioNTech COVID-19 Vaccine (BNT162b2)
The Pfizer/BioNTech (BNT162b2), another Covid-19 vaccine also works as an mRNA vaccine. The vaccine was developed by BioNTech and Pfizer who are the main agencies are overseeing the clinical trials, finances, logistics and worldwide manufacturing of the vaccine. Clinical efficacy studies highlight that it protects up to 90% of the exposed population. The vaccine is similarly delivered in 2 shots spaced 21 days apart. Storage and distribution are considered delicate as it requires ultra-cold temperatures of up to minus 75C but can be stored in a refrigerator for five days.
Apart from these three major vaccines, many other vaccines are expected to be released in the coming weeks within the first quarter of 2021. The development of the Sputnik V vaccine by Russia’s Gamaleya Research Institute has for instance already released its preliminary findings citing an approximate 92% effectiveness. China’s SARS-CoV-2 Vaccine (Vero Cell), Inactivated (lnCoV) by Sinopharm, and SARS-CoV-2 Vaccine (Vero Cell), Inactivated by Sinovacare also in their final stages of testing and are expecting approval by March 2021.
Concerning fears of potential side effects from the vaccines, health agencies have released data confirming flu-like side effects such as; chills, headaches, fever, and tiredness expected to fade away within the first and second day of getting the vaccines and should go away in a few days.
Research and funding challenges
As the COVID-19 vaccination efforts are currently underway, concerns remain across various fronts of the supply chain including: manufacturing, funding, logistics, storage, and mass administration. Moreover, scientists and health experts have voiced concerns over the potential for limited adherence, and the looming inadequacies of achieving the required herd threshold. It is estimated that to achieve herd immunity, up to 60-80% of the population and more ought to be immunized to prevent the fast spread of the virus. When extrapolated, the figures add up to billions of people, a statistic that may presently seem over ambitious.
Expected adherence challenges have already generated efforts on strategies to improve adherence including the need for increased financial incentives and funding. A body of controlled trials have confirmed the efficacy of incentivizing vaccine adherence in common vaccines such as the hepatitis B virus (HBV). Several reviews on the influenza virus studies provide support for the effectiveness of financial incentives to promote both initial vaccination and adherence rates. It is expected that high vaccine adherence will significantly improve herd immunity. All these findings put additional strain on funding incentives as huge scale manufacturing for billions of doses is required globally. Research is however still needed to confirm if these statistics will rise if the more transmissible strains of the SARS-CoV-2 continue to spread widely.