US, learning from Zambia

US, learning from Zambia

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SARS-CoV-2 Variants of Concern in the United States—Challenges and Opportunities

JAMA, 17th February, 2021

Rochelle P. Walensky, MD, MPH1; Henry T. Walke, MD, MPH1; Anthony S. Fauci, MD2

January 10, 2020, the first genomic sequence isolated in Wuhan

As of February 3, 2021, 468,000 sequences uploaded to public domain

3 specific viral lineages reflecting VOCs, B.1.1.7, B.1.351, and P.1.

B.1.1.7 lineage

September 2020, first detected, UK, December 2020

In at least 80 countries

In at least 33 US states

B.1.1.7, potential, reverse the present downward trend in new infections

Highlighted the risk of domestic and international travel

February 3, 2021, B.1.1.7 variant in the US is now approaching 1%, with prevalence in some states exceeding 2%

B.1.351 lineage

October 2020, South Africa, December 2020

In at least 41 countries

South Carolina and Maryland

Demonstrated reduced response to previous ‘wild type’ antibodies

Lymphocyte response may well be the same

P.1 lineage

December 2020, travellers from Brazil



B.1.351 variant

Early December to 22 of 23 samples (96%) sequenced

December 2020 to early January 2021

16-fold increase in COVID-19 incidence

The possibility of a similar experience in the US is a real threat


Level of community transmission must be aggressively decreased
consistent use of face masks,

physical distancing,

restrictions on high-risk and high-capacity settings,

frequent hand washing,

delaying travel,

widespread diagnostic testing and screening to swiftly identify and isolate infectious individuals,

particularly those who are asymptomatic, and quarantine contacts


Increased genome sequence surveillance


CDC’s 750 samples per week, to more than 6000


Accelerate SARS-CoV-2 vaccination nationally and globally

CDC is leading a comprehensive suite of studies to assess the actual effectiveness of these vaccines

Looking out for breakthrough infections

Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine

NEJM, (December 31st)

A two-dose regimen of BNT162b2 conferred 94.8% protection against Covid-19 in persons 16 years of age or older

After 1 dose, efficacy = 52.4%

NEJM, (17th February)

But if you take data after 2 weeks ….

One Pfizer dose, vaccine efficacy of 92.6% (based on FDA data)

One Moderna dose, vaccine efficacy of 92.1% (based on FDA data)

Uncertainty about duration of protection with a single dose

Administration of a second dose within 1 month, little added benefit in the short term

Leaving high risk groups completely unprotected

Postponement of the second dose is a matter of national security that,

if ignored, will certainly result in thousands of Covid-19–related hospitalizations and deaths this winter in the United States

hospitalizations and deaths that would have been prevented with a first dose of vaccine.