11 August 2022 Episode 280 Update on Long Covid, reinfection and hybrid immunity

Thu, 08/11/2022 - 22:04

Episode 280 Long Covid, reinfection and hybrid immunity

Dear colleagues,

A short episode, easily “digestible”, based on a re-arrangement of hint by Patrick Smits



Ep 280-1: Cheng-Ying Ho, JAMA Neurology: Olfactory damage as reason for anosmia/ageusia?

A controlled post-mortem study found that COVID-19 infection is associated with axon injuries and microvasculopathy in olfactory tissue, suggesting that this is the basis for severe and even permanent  olfactory dysfunction in COVID-19 infection.  


Ep 280-2: Ballering Lancet 6 August 2022: Large cohort of > 4000 COVID and > 8000 matched controls between April 2020 and August 2021 shows excess of 12.7 % of post COVID symptoms  (after 90-150 days).


Ep 280-3: Lyudmyla Kompaniyets  MMWR 5 August 2022 Post-COVID in US children and adolescents March 2020-Jan 2021


Compared with patients aged 0–17 years without previous COVID-19, those with previous COVID-19 had higher rates of acute pulmonary embolism (adjusted hazard ratio = 2.01), myocarditis and cardiomyopathy (1.99), venous thromboem­bolic event (1.87), acute and unspecified renal failure (1.32), and type 1 diabetes (1.23), all of which were rare or uncommon in this study population.


COVID-19 prevention strategies, including vaccination for all eligible persons aged ≥6 months, are critical to preventing SARS-CoV-2 infection and subsequent illness, and reducing the public health impact of post-COVID symptoms and conditions among persons aged 0–17 years.


Ep 280-4: Hon Klein 10 August 2022 Distinctive immune profiling in long COVID


Most striking = low cortisol levels in long COVID(LC): about half of convalescent covid (CC) and healthy controls (HC)


Changes in circulating mononuclear cells:

  • increases in non-classical monocytes, activated B cells, double-negative B cells, exhausted T cells, and IL-4/IL-6 secreting CD4 T cells,
  • decreases in conventional Dendritic Cells type 1 and central memory CD4 T


Changes in antibodies:

  • elevated to SARS-CoV-2 antigen
  • elevated to herpes lytic antigens
  • NO change in auto-Ab

Suggestive of persistent SARS-CoV-2 antigen, reactivation of latent herpesviruses, and chronic inflammation,  but not consistent with auto-immunity.




Ep 280-5: Sharon Tan NEJM 11 August 2022:  Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age in Singapore Jan-April 2022



Ep 280-6: Christian Holm SSRN 10 August 2022 Risk of reinfection, vaccine protection, and severity of infection with the BA.5 omicron in Denmark  April-June 2022


High protection against BA.5 by hybrid immunity = prior omicron infection in triple-vaccinated individuals, and similar vaccine effectiveness for BA.5 infection as currently for BA.2.


BA.5 infection was associated with an increased risk of hospitalization, but low overall


Ep 280-7:  Suryawanshi Nature Review of Immunology August 2022 Complex picture of hybrid immunity


Protection after different immune-conferring events.

a | Emerging Omicron sub- variants escape immunity conferred by infection with non- Omicron SARS- CoV-2 variants.

b | A second dose of mRNA vaccine gives moderate protection for non- Omicron and limited protection against Omicron variants 6–8 months post- vaccination.

c | Hybrid immunity elicited by BA.1 breakthrough infection in vaccinated individuals (2 doses) provides cross- variant protection but causes neutralization escape for newly emerging Omicron variants.

d | Hybrid immunity generated by Delta infection in vaccinated individuals elicits broader protection against non- micron and Omicron (BA.1) variants.

e | Compared with B.1.617.2, immune imprinting generated by infection with Wuhan/B.1.1.7 , vaccination (3 doses) and Omicron reinfection decreases Omicron neutralizing antibodies and T cell recognition, which may increase chances of Omicron reinfection. Consistent with Reynolds et al..


Ep 280-8: Sarah Zhang in the Atlantic: A common language discussion on how long the Coronavirus can keep reinfection us?  Well, probably indefinitely….


Best wishes,