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The vaccine described in the paper published in The Lancet was explicitly described as using an replication deficient Ad5 vector, while the vaccine received by

The vaccine described in the paper published in The Lancet was explicitly described as using an replication deficient Ad5 vector, while the vaccine received by Brazil seems to have been replication competent. Considering Slovakia also said that Russia did not deliver a vaccine matching the characteristics of the one in The Lancet, I think those data are basically irrelevant now.

sudosysgen 5y ago
The vaccines delivered to Brazil also have a replication deficient Ad5 vector, Anvisa says that among the vast majority of replication deficient vectors some replication-able viruses were present. There is pretty much no chance at all that this affects efficacy.
- sanxiyn 5y ago
  > Anvisa says that among the vast majority of replication deficient vectors some replication-able viruses were present. Do you have the source for this claim? Linked Anvisa slides page 6 says "todos os lotes" (all lots) had replicating virus. I agree this is about quality control and it is extremely unlikely to affect vaccine efficacy. (If anything, it would improve vaccine efficacy.)
  - sudosysgen 5y ago
    I will try to find the source again, however I would read todos os lotes as saying that there are detectable replicant viruses. Replicant viruses do not carry the spike protein, they don't contribute to antigen protection.
    - bonzini 5y ago
      > Replicant viruses do not carry the spike protein, they don't contribute to antigen protection. Are you sure? Do you mean that all of them must have had recombination that added the E1 gene and dropped the spike protein?
      - sudosysgen 5y ago
        Indeed. So if a virus is able to replicate it must have a replication-competent E1 gene which normally encodes for the spike
  - ArgyleSound 5y ago
    > I agree this is about quality control and it is extremely unlikely to affect vaccine efficacy. (If anything, it would improve vaccine efficacy.) I don’t think you can say this with much certainty, if the viruses either regained or never lost E1, it’s also possible that the same is true with E3 which modulates immune response. Also, either of these genes could’ve replaced the Coronavirus spike protein.
orr721 5y ago
The problem in Slovakia is that the delivered vaccines are in the form of a lyophilisate (pulver), one dose per vial. The vaccine described in Lancet was in liquid form, five doses per vial.

sudosysgen 5y ago

The vaccines delivered to Brazil also have a replication deficient Ad5 vector, Anvisa says that among the vast majority of replication deficient vectors some replication-able viruses were present. There is pretty much no chance at all that this affects efficacy.

sanxiyn 5y ago
> Anvisa says that among the vast majority of replication deficient vectors some replication-able viruses were present. Do you have the source for this claim? Linked Anvisa slides page 6 says "todos os lotes" (all lots) had replicating virus. I agree this is about quality control and it is extremely unlikely to affect vaccine efficacy. (If anything, it would improve vaccine efficacy.)
- sudosysgen 5y ago
  I will try to find the source again, however I would read todos os lotes as saying that there are detectable replicant viruses. Replicant viruses do not carry the spike protein, they don't contribute to antigen protection.
  - bonzini 5y ago
    > Replicant viruses do not carry the spike protein, they don't contribute to antigen protection. Are you sure? Do you mean that all of them must have had recombination that added the E1 gene and dropped the spike protein?
    - sudosysgen 5y ago
      Indeed. So if a virus is able to replicate it must have a replication-competent E1 gene which normally encodes for the spike
- ArgyleSound 5y ago
  > I agree this is about quality control and it is extremely unlikely to affect vaccine efficacy. (If anything, it would improve vaccine efficacy.) I don’t think you can say this with much certainty, if the viruses either regained or never lost E1, it’s also possible that the same is true with E3 which modulates immune response. Also, either of these genes could’ve replaced the Coronavirus spike protein.

orr721 5y ago

The problem in Slovakia is that the delivered vaccines are in the form of a lyophilisate (pulver), one dose per vial. The vaccine described in Lancet was in liquid form, five doses per vial.