A Texas wedding this past April became an unintentional experiment in vaccine efficacy. All 92 guests were vaccinated but COVID disease broke through in six people. Four of them got one of the mRNA vaccines and developed one mild illness. Two got Covaxin, a vaccine developed in India. Both became very ill and one subsequently died. The culprit was the dangerous delta variant.
It's only a case study, but the implications are intriguing. A pre-print on the medRxiv site gives us an anecdotal but nonetheless interesting case study of a "real-life comparison" of different vaccines. I put this phrase in quotes because while this study cannot provide a ranking of the efficacy of the different vaccines, it is nonetheless thought-provoking. What the paper does show rather convincingly is that a new COVID variant, the delta variant, is not just another Greek letter.
According to the Baylor School of Medicine paper, ninety-two guests attended an April 2021 wedding in the Houston area. All guests were required to be vaccinated, but they received different vaccines. Here is a summary from the paper.
- The wedding took place outside under an open tent.
- In April, the delta variant, originally from India, was not widespread in the US.
- Two guests from India, both of whom tested negative before their flight, became ill.
- Both received the Covaxin (1) vaccine 10 days before the flight. PCR testing indicated that both were infected with the delta variant.
- Four other people in close contact with the guests from India became ill, also from the delta variant.
Additional information on the people who were infected is shown in Table 1 below.
Source: T. Farinholt, Ph.D., et. al. https://doi.org/10.1101/2021.06.28.21258780
Both guests who received the Covaxin vaccine became seriously ill; one (Patient 0a in Table 1) died a month later. The others who became ill had received either the Pfizer/BioNgen or Moderna vaccine; their illnesses were mild. This suggests but does not prove that the mRNA vaccines are more effective against the COVID delta variant. Note that all guests who became ill were 50 or older.
Don't Mess With Delta
It is becoming clear that the delta variant isn't "your father's virus." It is more transmissible, causes more serious illness in the unvaccinated, and can cause disease, almost always mild, in vaccinated individuals (2). It is now the predominant variant in the US. Although there have been differing opinions about whether delta can evade antibodies generated from the current vaccines, it is now clear, from the Baylor study, that it can.
What's Next? Masks??
To those of us who are fully vaccinated, life is pretty much back to normal. Running around with a mask is just a distant and unpleasant memory. But it may become more than a memory. The World Health Organization recently issued some controversial advice, advising that masks should be used, something that none of us could have imagined a few months ago.
“People cannot feel safe just because they had the two doses. They still need to protect themselves...“Vaccine alone won’t stop community transmission...People need to continue to use masks consistently, be in ventilated spaces, hand hygiene ... the physical distance, avoid crowding. This still continues to be extremely important, even if you’re vaccinated when you have a community transmission ongoing.”
Mariangela Simao, M.D., assistant director-general for access to medicines and health products, WHO
The take-home message? The mRNA vaccines are almost certainly more effective than the others in staving off COVID disease, but the delta variant can, in some instances, "break through." But even when it does, the chance of serious illness for people who received the Pfizer or Moderna mRNA vaccine is minuscule. The jury is still out on the other approved vaccines, but there is a reason for concern. We are not done with COVID, nor is it done with us.
Get the damn vaccine. Seriously.
NOTES:
(1) Covaxin is the first COVID vaccine developed in India. It is manufactured made by Bharat Biotech
