Breakthrough infections after two shots: 50% in 1 month, 75% in 3 months.

Breakthrough Infections After Two Shots: 50% In 1 Month, 75% In 3 Months.
Source: Medrxiv

Preprint research from the University of France in Lyon answered the question. How soon can you have a breakthrough infection after complete vaccination?

They studied 1,630 fully vaccinated individuals from February to July 2021. 94.1% of the samples available for gene sequencing have the Delta variant.

Several vaccine strategies are available in France. It can be homologous or the same vaccine for both shots or heterologous where the vaccines are mixed. The vaccine strategies were:

  1. Homologous Pfizer-BioNTech or Moderna.
  2. Heterologous vaccination (mixed) with AstraZeneca and Pfizer-BioNTech 
  3. Single-dose vaccines Johnson & Johnson or AstraZeneca

Delta-VBI means a vaccine breakthrough infection from the Delta variant. Delta is the most predominant SARS-CoV-2 variant during the study period.

The study answered several relevant questions.

Who among the vaccines has the most Delta VBI?

Pfizer was the most frequent vaccine breakthrough reported – 79.1% followed by Astra Zeneca ChadOx1 at 9.2% and Moderna at 7.0%

What age group had the most Delta VBI?

People below 50-years-old who had the Pfizer or the Moderna shots.

Were the breakthrough infections symptomatic or not?

All vaccine groups with breakthrough infections have mild symptoms in the majority.

Is there a difference between viral loads between the symptomatic or asymptomatic? 

The viral loads are higher among the Pfizer groups who are symptomatic than those without symptoms.

In the other vaccine groups, the viral loads are the same whether they have symptoms or not.  Viral loads were measured by the cycle threshold (Ct) values of the PCR tests, and the lower the Ct, the higher the viral loads.

How soon do vaccine breakthrough infections happen?

50% of all VBI happened within one month after full immunization in the Pfizer, Moderna, Johnson & Johnson, and AstraZeneca vaccines. The age group with early Delta-VBI is mainly 14-49 years old

More than 75% of Delta VBI occurred within three months following full immunization regardless of vaccine strategy.

Summary

Briefly, mild breakthrough infections occurred three months after full immunization for all vaccine strategies. The symptoms are mostly benign, but they have high viral loads and are infectious to others.

According to the study, the reason for the high numbers of Delta-VBI occurring only one month after full immunization in young patients might be related to a change in masking and social distancing after full vaccination. 

This research confirms another investigation discussed at Study: Pfizer COVID shots are good for 90 days only. Booster shots every three months

Take-away Message

All of the COVID shots in this study have a short duration of protection in most people against SARS-CoV-2. Most of the breakthrough infections are mild.

Neutralizing antibodies against the SAR-CoV-2 variants wane fast. Fortunately, the variants that survive are less lethal, even if they are more transmissible. That’s the natural course of viral epidemics.

Natural immunity that is durable and robust beats vaccine-induced. You can read the epidemiological proofs at Ten Studies showing a low risk of COVID-19 reinfection among unvaccinated.

With that information, will you get the booster shots and be exposed to the adverse effects?

 

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  5. COVID Vaccines are Non-Sterilizing and Can Lead to More Infectious Variants
  6. How effective are the Pfizer and AstraZeneca vaccines against COVID-19 household spread?
  7. Breakthrough Cases Spread COVID-19 as Easily as the Unvaccinated
  8. Study: Vaccination Does Not Affect the Number of COVID-19 Cases
  9. CDC Report shows 25% Mortality in Breakthrough Cases
  10. Durable Immunity from Pfizer COVID-19 Vaccine Lasts only Six Months

Reference:

Bal et al. Investigation of Vaccine Breakthrough Infections by Vaccine strategy during the Delta Variant Wave in France. 

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