CME INDIA Presentation by Dr. Rajeev Jayadevan, MD, DNB, MRCP, ABIM (Med) ABIM (Gastro), NY. Vice Chairman, Kerala state IMA Research Cell. Member, National IMA Task Force on Corona Epidemic, Cochin.

New two studies (Not Peer reviewed) cast light on two vital emerging facts

  1. No difference in viral load between vaccinated and unvaccinated people who developed SARS-CoV2 virus infection.
  2. All vaccines are known to prevent severe disease and death.

Study No – 1

Authors observed low Ct values (<25, which means higher viral load) in 212 of 310 fully vaccinated (68%) vs 246 of 389 (63%) unvaccinated individuals. This was confirmed by virus culture.

This implies that vaccinated people can spread the virus as easily as the unvaccinated.

  • This emerging information needs to be incorporated in public policies.
  • “Vaccine mandates” are increasingly becoming irrelevant – because unvaccinated people aren’t any more dangerous to those around them than vaccinated people are. Breakthrough infections are common now.
  • In other words, more studies are now showing that vaccinated people could spread virus as efficiently as unvaccinated people.

The old concept of “only vaccinated people are safe to be with” has to change.

Study No – 2

How effective is vaccination in real life?

 * Important observations from the Max hospitals/ CSIR-IGIB study.

  • 25.3% got breakthrough infection (BTI) within 2 months of vaccination (2 doses).
  • Post vaccination Anti Spike antibody level was no different between those who got BTI and no BTI (see graph). This means that checking antibody level after vaccination will not tell us whether we will get reinfected or not. Routine antibody testing after vaccination, as discussed earlier, will not help.
  • Those who had prior natural infection did very well, even with 1 dose. Only 2.5% of those with past infection got reinfection.
  • The extraordinarily high antibody level required to stop delta was mostly seen among those with past infection (not by vaccination alone).
  • Authors conclude that breakthrough infections are far more common than previously reported.
  • One dose vaccine did not seem to prevent BTI in this study, 48.4% of these people (those without the added protection of past infection) got infected during the delta surge.

No deaths or severe disease reported among 597 vaccinated healthcare workers, despite high % of breakthrough infections

  • Most infections were unrecognized; the study was primarily based on serial serology in two groups of healthcare workers – Max hospitals and CSIR-IGIB.
  • This means we need to redefine some narratives:
  • “Herd immunity,” as the authors point out, will not happen with either vaccination or past infection, because reinfections and breakthrough infections (and therefore silent spreading in the community) are commoner than we think. The good thing is that these reinfections or BTI are mild or asymptomatic so far.
  • The assumption that vaccines will stop transmission is wrong, as shown by the high rate of (1 in 4) breakthrough infections among the fully vaccinated in just 2 months
  • These real-life studies are critical in making policy decisions for the future. The implications are so different from the exaggerated narrative created by phase 3 trials of vaccines that claimed e.g., “90% plus protection.”

This was widely misunderstood as “being bulletproof” and some nations (US, Israel) even said “no more masks” – only to regret it later.

  • The real facts need to be communicated to the public, so that they will understand the true purpose of vaccination: that is (and always was) to prevent severe disease and death.
  • Knowing this is important because people need to continue wearing masks and follow standard precautions – regardless of whether they are vaccinated or not.
  • If this is not communicated, vaccinated people may mistakenly disregard precautions and spread disease.
  • For those with past infection, one dose vaccine appears to be enough – and this is biologically plausible. (One dose will boost immunity based on anamnestic response to memory cells created by past infection).
  • Multiple other studies are pointing in the same direction. This needs the attention of policy makers – and could solve the problem of vaccine shortage.

CME INDIA Learning Points

  • It is now well known that the SARS-CoV-2 Delta variant and its sub lineages (B.1.617.2, AY.1, AY.2, AY.3; can cause high viral loads, are highly transmissible, and contain mutations that confer partial immune escape.
  • High viral loads in nasal swabs have been found irrespective of vaccine status, during a time of high and increasing prevalence of the Delta variant.
  • New data substantiate the idea that vaccinated individuals who become infected with the Delta variant may have the potential to transmit SARS-CoV-2 to others.
  • It is at present crystal-clear recommendation that vaccinated individuals should continue to wear face coverings in indoor and at congregate settings
  • New data shows that during a severe SARS-CoV2 Delta-variant outbreak in Delhi, the Delta-variant caused frequent unrecognized breakthrough infections in adequately immunized subjects, reducing any herd-effect of immunity.
  • We do require reinstatement of preventive measures such as masking as recent data suggests that Delta infections have higher viral loads, with no difference between vaccinated and unvaccinated.


1. Shedding of Infectious SARS-CoV-2 Despite Vaccination when the Delta Variant is Prevalent – Wisconsin, July 2021.Kasen K. Riemersma, Brittany E. Grogan, Amanda Kita-Yarbro, Peter Halfmann, Anna Kocharian, Kelsey R. Florek, Ryan Westergaard, Allen Bateman, Gunnar E. Jeppson, Yoshihiro Kawaoka, David H. O’Connor, Thomas C. Friedrich, Katarina M. Grande.medRxiv 2021.07.31.21261387; doi:

2. High failure rate of ChAdOx1-nCoV19 immunization against asymptomatic infection in healthcare workers during a Delta variant surge: a case for continued use of masks post-vaccination.Rajat Ujjainiya, Akansha Tyagi, Viren Sardana, et al..medRxiv 2021.02.28.21252621; doi:

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