COVID-19 UPDATE / Immunity and Vaccine Development

In this edition:

1.     Only 25 COVID-19 vaccine doses administered in low-income countries

2.     Sinovac says its COVID-19 vaccine more effective with longer dosing interval

3.     WHO panel says officials worldwide failed in the early pandemic response

4.     Emirates offers Pfizer, Sinopharm vaccines to staff

5.     Post-vaccination deaths lead to reinforcement of individual assessment for elderly

6.     Mass vaccination clinic in Scotland: NHS Louisa Jordan

7.     CDC warns new COVID variant could be dominant strain by March

8.     Tweet from Dr Tom Frieden regarding increasing death rates

9.     What is “herd immunity”?

10.  Johnson & Johnson vaccine update

1.     Only 25 COVID-19 vaccine doses administered in low-income countries

The world is on the brink of a “catastrophic moral failure” in the distribution of COVID-19 vaccines, with just 25 doses administered across all poor countries compared with 39 million in wealthier ones, the Guardian reports Tedros Adhanom Ghebreyesus said at the WHO Executive Board meeting on 18 January.

Dr Tedros said it was not fair for younger, healthy people in richer nations to get injections before vulnerable people in poorer states.

Guinea is the sole low-income country to have delivered any shots so far, last week providing doses of the Russian Sputnik vaccine to a mere 25 people, including its President.

The World Bank defines low-income countries as those with an income of USD $1,035 per person per annum, or lower. See list of the 29 low-income countries on this World Bank info page.

2.     Sinovac says its COVID-19 vaccine more effective with longer dosing interval

Reuters reports that on 18 January Sinovac said that a clinical trial in Brazil had found that among 1,394 participants who received their two doses three weeks apart, instead of two weeks apart, the efficacy was nearly 70%.

This contrasts with efficacy rates of 50.4% published last week when the standard two weeks between doses protocol was used.

The Sinovac spokesman cautioned that this new data is less robust than the overall finding of 50.4%.

3.     WHO panel says officials worldwide failed in the early pandemic response

“Governments and public health organizations around the world responded slowly and ineffectually to the coronavirus outbreak, according to an interim report by a World Health Organization (WHO) panel that laid bare a yearlong cascade of failures,” reports the New York Times.

“’We have failed in our collective capacity to come together in solidarity to create a protective web of human security,’ the Independent Panel for Pandemic Preparedness and Response wrote.

“Many of the failings, such as the inability of governments to obtain protective equipment, have long been painfully clear. But the report is stark in its assessment that, time and again, those who were responsible for protecting and leading too often failed to do either.”

4.     Emirates offers Pfizer, Sinopharm vaccines to staff

Reuters reports that Emirates airlines began offering employees vaccinations against the COVID-19 on 18 January, with priority given to cabin crew, pilots and other operational staff. The airline’s management say global vaccination is key to any recovery for the travel industry, which they believe could happen this year if vaccines are rolled out at scale.

5.     Post-vaccination deaths lead to reinforcement of individual assessment for elderly

After reports of COVID-19 vaccination-associated deaths in the elderly, the Norwegian Medicines Agency has again advised doctors to assess each case individually prior to vaccination.

According to a press release, of the deaths associated with COVID-19 vaccination, at least 13 were assessed. All deaths occurred in the first few days of vaccination. Common adverse reactions to mRNA vaccines, such as fever and nausea, may have led to a fatal outcome in some frail patients. Reuters reports that the “Norwegian Institute of Public Health (FHI) said its guidelines remained the same.

An average of 400 people die each week in Norwegian nursing homes and long-term care facilities, the country’s Institute of Public Health said in a statement.

6.     Mass vaccination clinic in Scotland: NHS Louisa Jordan

NHS Louisa Jordan is part of NHS Scotland’s response to COVID-19.  It is based at the SEC Centre, Scotland’s largest exhibition centre, located in Glasgow. It is expected that 5,000 COVID-19 vaccines will be administered each day in collaboration with NHS Greater Glasgow and Clyde (NHSGG).

7.     CDC warns new COVID variant could be dominant strain by March

The US Centers for Disease Control (CDC) says the “UK” B.1.1.7 variant has been found in ten US states so far and could become the dominant US strain by March 2021.  This could fuel a huge increase in COVID-19 cases.

The variant is believed to be up to 70% more transmissible than the current version of the virus circulating in the US.

Its rapid spread will:

·       Increase the burden on health resources

·       Increase the need for better adherence to mitigation strategies, such as social distancing and mask-wearing

·       Increase the percentage of the population that needs to be vaccinated to achieve protective herd immunity to control the pandemic

8.     Tweet from Dr Tom Frieden** regarding increasing death rates

“Very concerning death rate increases in the UK, Ireland (note horrifying shape of curve), S Africa.

More infectious virus → more infections → more deaths.”

Chart: Daily new deaths per million people.  Currently UK = 1.5 X US & SA. This will likely change of when B.1.1.7 becomes the predominant in the US.

** Dr Tom Frieden was Director of the US CDC from 2009 to 2017.

9.     What is “herd immunity”?

Here we have summarised a new paper which is ready for publication in Current Biology.

In short, herd immunity is when the spread of an infectious disease is limited by the depletion of susceptible hosts…due to immunity.

But what is immunity?  The Miriam Webster dictionary defines immunity as “a condition of being able to resist a particular disease…”. It goes on: “In most cases, if you are immune to something, it has no effect on you…”

If a sufficient proportion of the population is immune – above the “herd immunity threshold” – then transmission generally cannot be sustained. Maintaining herd immunity is therefore critical to long-term disease control.

In 1927 William Kermack and Anderson McKendrick proposed the first models splitting a population into individuals who are susceptible, infected, or recovered.  They studied the rates of movement between these classes and showed that epidemics typically produce a hump-shaped curve, encapsulating an exponential growth phase in infections, followed by a peak and subsequent decline in cases.

Reaching herd immunity therefore does not mean the end of an epidemic – a common misconception – as many individuals will continue to be infected while cases decline.  For example, when R0 = 3 the herd immunity threshold is 67%; vaccinating this proportion will prevent an epidemic.

But if immunity is acquired naturally, then the epidemic will only peak when 67% have been infected and by the end of the epidemic 90% will have been infected. Achieving herd immunity simply means that R0 < 1 and so cases will decline from their current level.

Common misconception

An important, but often overlooked principle of herd immunity, is that it operates at a local level, and so the distribution of immunity in the population is crucial. Therefore, one should not assume that herd immunity has been reached simply because an epidemic has peaked.

Indeed, following the first waves of COVID-19, there were suggestions that many countries had achieved herd immunity since cases were in decline. However, serological testing revealed that relatively few people had been infected during the first wave (~5–10% in most cases).

A resurgence of cases in late 2020 confirmed that herd immunity had not been reached. With no evidence of widespread reinfections or pre-existing immunity, the most logical explanation is that public health interventions (NPIs) rather than herd immunity caused the epidemic peaks in early 2020.

10.  Johnson & Johnson vaccine update

The Johnson & Johnson/Janssen vaccine candidate uses adenovirus vector technology and is likely be a single-dose treatment, unlike the Pfizer, Moderna, AstraZeneca and Novavax candidates, which require two doses.

Results of phase 1/2a trials, recently published in the New England Journal of Medicine, found the vaccine was “safe and immunogenic in both younger and older adults”. It showed the vaccine was “generally well tolerated across all study participants” and created COVID antibodies in all participants aged 18 to 55. These neutralising antibodies remained stable through Day 71, currently the latest timepoint available in this ongoing study.

Phase 3 trials are still being carried out, with results due to be published in late January.

It is likely that the vaccine will be able to be stored and transported at standard refrigerator temperatures.

International SOS data indicates that the following countries have ordered or purchased Johnson & Johnson vaccine: Austria, Belgium, Brazil, Canada, Chile, Colombia, Croatia, Cyprus, EU, Iceland,

Israel, Italy, Mexico, New Zealand, Panama, Philippines, South Korea, Spain, UK and US.