27 April Episode 134 What everybody want to know about Indian vaccines

Tue, 04/27/2021 - 16:11

….is how good they protect against SARS-CoV-2 and especially against the “Indian variant” (B1.617).

Well, I hope to offer you some cautious preliminary answers.

Covishield is a license of Astra-Zeneca, hence the Oxford Adenovirus ChAdOx-1 nCoV19

Covaxin is an inactivated vaccine BBV152 which has been developed by the Indian Bharat Co.

 

Ep 134-1 is a general press paper dated April 21, by a New Delhi based journalist Milan Sharma, who quotes a spokesperson from the Indian Council of Medical Research: (only)  0.04% people tested Covid-19 positive after 2nd dose of Covaxin, 0.03% after Covishield. 

A very high protection indeed, but these “real world data” have not been published in preprint.

Indian Covishield data

The paper refers to trial data showing 70 % efficacy for Covishield (= Astra-Zeneca), but if you click, you end up in the Lancet paper if December  by Voysey on the ChAdOx1 nCoV-19 vaccine (Ep 95-5, that I sent yesterday) , which showed the very mixed results of trials in UK and Brazil, with a mean protection of 70 % against symptomatic COVID-19.

Ep 134-2 contains another press release by Rakesh Mishra, director of the Centre for Cellular and Molecular Biology, who claims that in vitro neutralisation assay show that both convalescent (prior infection) sera and Covishield-vaccinated sera offer protection against the B.1.617 variant

Indian Covaxin data

The paper (Ep 134-1 by Milan Sharma) also mentions 81 % efficacy for the inactivated Covaxin (=BBV152). However, there are no published results of a human phase 3 trial.

What you find indeed is

Ep 134-3 A: Nat Comm paper showing protective efficacy of  BBV152 with 3 different adjuvants in macaques

Ep 134-3 B is a very recent iScience paper, showing in various small animal models that the preferred adjuvant Algel-IMDG (containing a TL7/8 agonist)  elicits clear-cut Th1 responses, while in fact the neutralizing antibody responses  are rather similar whether only Algel or Algel-IMDG are used

Hence, this inactivated Covaxin is prepared rather similarly as the Chinese vaccines, but it has as a surplus this IMDG adjuvant that activates T cells more than AlOH alone (which is the only adjuvant in the Chinese vaccines).

Ep 134-4 in the Lancet summarizes the results of human phase 1 and 2 trials. The seroconversion rate is 96 % with 2 doses of 6 µg of the BBV152 Algel-IMDG with an interval of 28 days.  Neutralizing titers are slightly higher than in convalescent sera and remain stable for at least 3 months.

Ep 134-5 is a preprint, showing that sera from Covaxin-vaccinated subjects neutralize the UK variant B.1.1.7 and the WT (with D614G) equally well.

Ep 134-6 is another very recent preprint (23 April).  It shows that sera from BBV152 vaccinated or naturally infected subjects are equally potent at neutralizing the  Indian variant (B.1.167) (Fig 1 E p. 10), but neutralizing capacity of BBV152 vaccinee sera is significantly lower against the Indian variant, as compared to the WT D614G and the UK variant (Fig 1D).  The differences, is however “only twofold”.

Some real world data

Ep 134-7 a medRxiv preprint of 20 April shows that almost half (48 %) of HCW was already seropositive for SARS-CoV-2 before Covishield vaccination. This percentage increased to 79 % 14 days after the first dose.  

Ep 134-8 a medRxiv preprint of 13 April, showing that the responder rate and median rise in anti-spike antibody after the first dose was significantly higher in Covishield vs. Covaxin recipient (86.8 vs. 43.8%; 61.5 vs. 6 AU/ml; both p<0.001).

We are eagerly awaiting published efficacy results after full vaccination.

Conclusion: Both vaccines will be very useful to contain the Indian epidemic. It remains to be seen what the exact level of protection against the Indian variant will be….

Some other news: an advice of the (Belgian) Risk Assessment Group-COVID Animals

  • It is well known that various pet animals (cats, dogs, ferrets and hamsters) are susceptible to SARS-CoV-2, but in Belgium only 1 cat has been found positive
  • Next to commonly known symptoms, also myocarditis can occur especially with the British variant.
  • If an owner has Covid-19, he or she should limit contact with their companion animals as much as possible.

Best wishes,

Guido

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