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Herd Immunity Falls Off the Table

Published on February 9, 2022

New Variants: Omicron BA.2 is More Concerning Than Omicron BA.1

Source

We need to stay ahead of the game by recognizing that new variants are already here.

The Omicron BA.2 subvariant is as different from BA.1 as Delta is from the original wild type strain, prompting concern. Cross immunity between BA.1 and BA.2 may be low – infection with one strain may not provide enough protection against the other, we need to plan ahead. 

It is essential that the world continues to collaborate to monitor new variants as they emerge, and continue measures that reduce transmission.

UK Health Security Agency risk assessment for SARS-CoV-2 variant BA.2 Source

Delta+Omicron recombination is a serious risk

Source

Recombination is a process common to viruses that combines parts of variants to make new ones, allowing viruses to rapidly overcome protective barriers like vaccine and infection induced immunity.  

The Delta variant remains in circulation alongside Omicron. Considering the unprecedented massive number of infections globally, the possibility of the emergence of a recombinant super-mutant that demonstrates both the transmissibility of Omicron and the severity of Delta – or a so-called “Deltacron” strain – is significant.

What’s Endemicity Like? – Herd Immunity Falls Off the Table

Recent scientific studies show that herd immunity by infection is not a viable exit strategy even at the cost of mass death and disability: no place on earth has reached herd immunity by any combination of infections and vaccinations, against Omicron. People can be reinfected by Omicron after an Omicron infection (see figures below). A Vaccine+ strategy is a must.

Vaccinated, boosted individuals are (B) much less well protected from Delta than from WT (original variant), and (D) very poorly protected from Omicron infection.
Delta breakthrough infection provides significant protection from reinfection by Delta (top left), but provides little protection from Omicron infection (top right). Omicron infection does not protect from either Delta infection (bottom left), or – of critical importance – against reinfection by Omicron (bottom right). Figures source

Guidance

University COVID Best Practices Winter/Spring 2022 – (WHN + CAG)

Resources

Omicron

The rapid spread of Omicron is due to its advantage over Delta among the vaccinated. Combined protective measures are therefore needed to curb transmission and the continued emergence of novel variants. (medRxiv) When low risk is too much risk: Jana Schroeder on the Perils of Germany’s Omicron Strategy. (Der Spiegel) Pandemic-Fueled Shortages of Home Health Workers Strand Patients Without Necessary Care. (KHN)

Policy

Boston Public Schools install air quality sensors in every classroom. Others should follow suit. (Boston Public Schools)


Diverse types of social media misinformation contribute to vaccine hesitancy and require decisive action by health authorities in establishing clarity about vaccine risks and benefits. (Preprint)

Assessing the impact of the pandemic in children and adolescents: SARS-CoV-2 infection and beyond. (Lancet)

Persistent symptoms found among teens previously diagnosed with COVID-19.Physical and mental health 3 months after SARS-CoV-2 infection (long COVID) among adolescents in England. (Lancet) 

Hundreds of scientists call on the UK government to remove bureaucratic and legal obstacles to vaccine production by low and middle-income countries. (Global Justice Now)

Economy

Coronavirus infections in truckers drive up vegetable prices in Hong Kong. (SCMP)


Pandemic disrupts “cheap and reliable shipping” well past 2022. (Indian Express)


The impact of the COVID-19 recession on Mexican households. Evidence from employment and time use for men, women, and children. (Rev. Econ. of the Household)


Pathways to improved management of mental health resilience in remote workforces. (BMC Public Health)

Mitigation

Development of a novel intranasal vaccine enhances immunity at mucosal surfaces and  shows promise in inducing cross-reactive immunity against subgenus of coronaviruses including SARS-CoV-2. (bioRxiv)

Use of masks lowers incidence of COVID-19 in childcare settings and decreases closures. (JAMA)

Covid-19 leads to long term cardiovascular pathology even among those without severe illness and hospitalization, and regardless of vaccination status. Long-term cardiovascular outcomes of COVID-19. (Nature Medicine)

Results from examination of NYC wastewater reveal reservoirs of unidentified SARS-CoV-2 variants likely developing in rodents. (Nature). And, Data: CDC launches National Wastewater Surveillance System. (CDC) 

Maternal vaccination associated with higher amounts of anti-spike antibodies in infants than maternal infection. Durability of Anti-Spike Antibodies in Infants After Maternal COVID-19 Vaccination or Natural Infection. (JAMA) 

Potential mechanism of SARS-CoV-2-associated neuroinflammation involves microglial inflammasome activation in SARS-CoV-2-exposed cells mediated by SARS-CoV-2 spike protein receptor binding domain interaction with microglia-expressed ACE2 receptors. (bioRxiv)

In Community,

-The WHN