For Convid-10 vaccines, effectiveness is the determinant of success. But speed matters, too. AstraZeneca and Pfizer are among the frontrunners in the race to develop a vaccine for the coronavirus, with the race also including Johnson & Johnson and Moderna Inc.
In the vaccine race, mRNA vaccines have the advantage. They are likely to be available earlier than most rivals.
Pfizer, which has teamed up with Germany’s BioNTech SE, are testing vaccines that use messenger RNA, a genetic material that instructs the body to make viral proteins that in turn trigger an antibody response—in this case against SARS-CoV-2, the virus that causes Covid. Pfizer might be first out of the gate; the company has said it could be ready to apply for authorization by late November.
Figure 1. Coronavirus Vaccine Tracker (nytimes.com; accessed on 11/01/2020)
Front-Runners — AstraZeneca and Pfizer
On 11/01/2020, Reuters reported that:
AstraZeneca Plc said on Sunday Britain’s health regulator had started an accelerated review of its potential coronavirus vaccine.
“We confirm the MHRA’s (Medicines and Healthcare Products Regulatory Agency) rolling review of our potential COVID-19 vaccine,” an AstraZeneca spokesman said.
In rolling reviews, regulators are able to see clinical data in real time and have dialogue with drug makers on manufacturing processes and trials to accelerate the approval process.
On 10/30/2020, Bloomberg also reported that MHRA had begun an accelerated review for the COVID-19 vaccine candidate from Pfizer Inc.
Figure 2. Different Covid-19 Vaccine Types
Figure 2. Different Covid-19 Vaccine Types
AstraZeneca (Andenovirus Technology)
AstraZeneca is using a viral vector technology that deploys an altered common cold virus to carry the genetic material of the coronavirus and produce an immune response.
AstraZeneca said on 10/26/2020 its COVID-19 experimental vaccine produces an immune response in both old and young adults. The vaccine also triggers lower adverse responses among the elderly, it said.
Pfizer (mRNA)
Figure 3. Global outlook from Barclays Research
Storage and Distribution Issues
The issue is acute for a new type of vaccine that uses messenger RNA (mRNA) to trigger an immune response. To prevent degradation, the vaccine needs to be stored and distributed at very cold temperatures, making it hard to administer jabs in conventional settings such as pharmacies. Wealthy countries at the front of the queue for jabs are best placed to deal with storage challenges
Here are the temperatures required for storage and distribution:
- AstraZeneca (andenovirus technology)
- normal fridge temperatures
- Moderna (mRNA)
- -20°C
- Novavax (recombinant protein vaccine)
- normal fridge temperatures
- Pfizer and BioNTecwhich (Andenovirus Technology)
- -70°C
- Pfizer said its temperature-controlled shipping containers solve some concerns. Once removed from the containers, the vaccine can be kept for up to a day at a temperatures between 2 and 8 degrees Celsius (36-46°F) — roughly the temperature of a normal refrigerator — or 2 hours at room temperature.
- Sanofi (recombinant SARS-CoV-2 Protein Antigen + AS03 Adjuvant)
- normal fridge temperatures
Yet even normal fridge temperatures can be tricky. The World Health Organization says half of all vaccines are wasted due to refrigeration failure. One Covid-19 vaccine candidate — made by US biotech Inovio — can be kept at room temperature, though doubts about its chances have sent shares down two-thirds since June.
Given the urgent need to arrest the pandemic, timing will trump convenience at first. But vaccines that are easier to handle could win out in the end.
References
- Gilead’s coronavirus drug: why experts are cautious on its prospects (ft.com)
- A COVID-19 vaccine: 5 things that could go wrong
- Covid-19 vaccine delivery faces problems, warns DHL
- Moderna COVID-19 vaccine appears to work as well in older adults in early study
- Moderna said the immune responses in those aged between ages 56 and 70, above age 70 and those 18 to 55-years-old were similar
- Moderna has never brought a vaccine to market before
- Iceland Has Very Good News About Coronavirus Immunity
- Inhaled Vaccines Aim to Fight Coronavirus at Its Point of Attack
- COVID-19 antibodies last at least three months; so do symptoms for many
- Eli Lilly Virus Antibody Trial Paused Due to Safety Concerns
- Characterizing COVID-19 antibodies for potential treatments
- Why and How Vaccines Work
- How much will a Covid-19 vaccine cost?
- Immunity from COVID-19 could last for up to 7 months, according to a new study
- Longitudinal observation and decline of neutralizing antibody responses in the three months following SARS-CoV-2 infection in humans
- Structural features of coronavirus SARS-CoV-2 spike protein: Targets for vaccination
- Inside Operation Warp Speed’s $18 Billion Sprint for a Vaccine
- Britain starts accelerated review for AstraZeneca's potential COVID-19 vaccine
- COVID vaccine breakthrough raises hopes, poses logistical headache
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