Coronavirus, Good News

New Zealand

Ruled out

Frozen food items or freight

Burning ember

Infection from returners

Cases, + 13 + 7 + 13 + 9 + 12 = 1643

Hospitalised, + 1 = 6

Long term immunity

It would be good if,

Antibodies provide “real-world” protection

Cellular immunity is long-lasting

Memory B and T lymphocytes

T helpers, suppressors, killers (cytotoxic)

Even in mild cases.

New Delhi 24%

Mumbai 24%

Moscow 21.7 %

Stockholm 10 %

New York 6.9 %

London 17.5 %

UK 6.2 %

Marion Pepper, immunologist, University of Washington

This is exactly what you would hope for

All the pieces are there to have a totally protective immune response

Smita Iyer, immunologist, University of California, Davis

This is very promising

This calls for some optimism about herd immunity, and potentially a vaccine

Professor Danny Altmann, Department of Immunology and Inflammation, Hammersmith Hospital, Imperial College

While this is a small study, it offers a remarkable, real-life, human experiment at a time when we've been short of hard-line, formal, proof that neutralising antibodies genuinely offer protection from re-infection

In short, it’s good news

Neutralizing antibodies correlate with protection from SARS-CoV-2 in humans during a fishery vessel outbreak with high attack rate

University of Washington IRB

Identification of immunological correlates would help research

Only animal models to date

Outbreak of SARS-CoV-2 on a fishing boat

Attack rate on board of 85.2% (104/122 individuals)

Predeparture serological and viral RT-PCR testing

Repeat testing after return to shore

Full data on 120 of the 122 crew (9 women)

18 day trip, crew member required hospitalization

Median follow-up of 32.5 days

104 individuals had a positive antigen test or seroconverted during the follow-up period

101 developed IgG antibodies within 50 days

Also

Three crew members seropositive prior to the boat's departure

None of these crew members with antibodies developed symptoms or tested antigen positive

Lab studies also showed their antibodies had neutralising activity

Presence of neutralizing antibodies from prior infection was significantly associated with protection against re-infection (p=0.002).

Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19

Center for Infectious Medicine, Stockholm

Virus-specific memory T cells have been shown to persist for many years after infection with SARS-CoV-1

Acute phase SARS-CoV-2-specific T cells display high cytotoxic activity

Correlated with various clinical markers of disease severity

SARS-CoV-2-specific T cells were detectable in antibody-seronegative family members

and individuals with a history of asymptomatic or mild COVID-19

Collective dataset shows that SARS-CoV-2 elicits robust memory T cell responses

akin to those observed in the context of successful vaccines

natural exposure or infection may prevent recurrent episodes of severe COVID-19 also in seronegative individuals.

SARS-CoV-2 induces robust memory T cell responses in antibody-seronegative and antibody-seropositive individuals with asymptomatic or mild COVID-19.

Functional SARS-CoV-2-specific immune memory persists after mild COVID-19

Study was approved by the University of Washington Institutional Review Board

The recently emerged SARS-CoV-2 virus is currently causing a global pandemic and cases continue to rise.

The majority of infected individuals experience mildly symptomatic disease

but it is unknown whether this can induce persistent immune memory that might contribute to herd immunity

Longitudinal assessment

Individuals recovered from mildly symptomatic COVID-19

To determine if they develop and sustain immunological memory

Recovered individuals developed SARS-CoV-2-specific IgG antibody

As well as virus-specific memory B and T cells

In some cases increased numerically over three months following symptom onset

Memory lymphocytes exhibited characteristics associated with potent antiviral immunity

Memory T cells secreted IFN-γ (interferon Gama) and expanded upon antigen re-encounter

Memory B cells expressed specific antibodies