1178: COVID-19 vaccine difficulties

Issues

1. Studies have not shown yet whether the vaccine can prevent transmission of SARS-CoV-2.
2. It is not known if people can become infected and transmit even with vaccination. Those who have been vaccinated could still continue to asymptomatically and unknowingly shed virus and spread the disease. The data from the Pfizer/BioNTech and Moderna vaccines describe protection from symptomatic disease. Pfizer reported170 infections (162 in the placebo group) in 41,000 participants. Moderna has reported 95 cases (90 in the placebo group) thus far in 30,000 participants.
3. The level of nasal carriage required for infection, and the duration of that, are not known. It is also not clear what the vaccine does on that.
4. People can expect to still be wearing masks and follow non-pharmaceutical public health measures. People may start eating in restaurants, going to theatres, and sporting events without masks.
5. Data should look at the duration of viral shedding and the amount of virus in nasopharyngeal swabs or nasal swabs over time.
6. Herd immunity will require 80% coverage, and that is not likely to happen until summer of 2021.
7. We can get there, and we have the doses, but there may be a significant proportion of people who turn them down; then this epidemic goes on and on and on. Brazilian President Jair Bolsonaro has said that he will not take a coronavirus vaccine.
8. A former Vice President and Chief Scientist of Pfizer, Dr. Michael Yeadon, in anarticle published in Lockdown Sceptics, wrote that there is no need for vaccines to eliminate the pandemic.
9. Oxford trial errors tells how the trials are being conducted.
10. With mucosal infections, one is expected to see less protection. Influenza vaccines, in a good season, offer nearly 60%. Enteric (intestinal) infection vaccines can provide 85-90% protection, but not in all parts of the world. Injectable polio vaccines for a mucosal infection is particularly good but it does not really protect against the mucosal component, the enteric tract.
11. Will it work in younger people?
12. Will it work in people who are immunocompromised?
13.  Can you give these vaccines to pregnant women?
14.  What would their safety record be?
15.  How long does protection last?
16.  What does the immune response look like?
17.  What is the B-cells component?
18.  RNA is very inflammatory. More reactions were seen in people who got the highest dose in the Moderna trial, and that dose is not being used for further studies.
19.  UNIP does not have a vaccine as expensive as the AstraZeneca vaccine $3 a dose.  The country needs something under 50 cents.
20.  We need single dose candidates: Vectored vaccines — measles, VSV or vaccines with an adjuvant. Bio E is collaborating with the Baylor College of Medicine on a protein-based candidate. Janssen’s vaccine is an adenovector vaccine which is planned as a single dose because it is a replicating vector. Bio E is also working with them.
21. Every mRNA vaccine is different. While the sequence coding for the stabilized spike may be the same, when making a vaccine, which is either enclosed within a lipid nanoparticle or integrated with it, one will have different levels of stability.
22. 2-6-degree temp: Gennova Biopharmaceuticals (mRNA vaccine); CureVac [Germany]; Pfizer is planning to modify its formulation. If there is a need for cryo-vials, then special kinds of glass is needed.
23. Auto-disabled syringes are costly. Glass vials are a challenge. We will need enough rubber stoppers and the aluminum foil that goes on top of the injection vials.
24. If we need to have vaccine vial monitors (VVMs) to monitor the temperature of vaccines and excursions, only one company in the world is authorized to make them.
25. mRNA vaccines — need sufficient nucleotides to manufacture the RNA on the scale that people want.
26. Failures of batches are a fact in the development of vaccines. Whether that will happen with mRNA?

[Sources: Medscape; Reuters; Healthwire; The Indian Express]

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA