Herd Immunity for Covid-19?

Have you noticed only politicians and some lay people talk about #HerdImmunity? Scientists and business people seem to be talking about #testing, cure and vaccines. Amazon is planning its own tests just for their own workforce. Some of my clients are doing the same. Chemicals for covid-19 diagnostic tests are hard to find but businesses may tap into their global connections to acquire them.

So what is herd immunity?

Herd immunity is an epidemiological concept coming from an idea that ultimately if enough people in a population are immune to a disease then it stops spreading. For instance, if 80 people out of 100 can’t get the disease than the 20 people who can get it remain protected because they may be unlikely to actually get exposed.   

Herd immunity can be achieved in a community in one of the two primary ways.

1) Vaccine access and acceptance:

If a significant number of people get access to the vaccine, they accept it and avail of the opportunity and become non carriers of the virus then even if 5% may not have gotten the vaccine, they may not get the disease because there may not be enough people to get it from. But we don’t yet have a vaccine for coronavirus.

2) Virus has a free rein: 

This is how the politicians have been speaking of herd immunity. Herd immunity is also connected to the argument that the best way to end the social distancing is to allow the virus to run free or at least almost free and in the end the population will achieve herd immunity. This sounds like a creative new idea rather than something horrifying that we should try to avoid at all costs. But let us remember that this only happens after VAST numbers in a population, get infected. So that requires us to “sacrifice the vulnerable on the altar of the economy in vast numbers.”

What kind of vast numbers of fatality might we be speaking of? As per some estimates, herd immunity for Covid-19 can occur after at least 60 to 70 percent of the population develops immunity.  That means at least 60 to 70 percent of the people have to first get infected. Moreover, these have to be random infections. That means, several people would die with a highly contagious virus running free in a society, before herd immunity is achieved.  This would overwhelm our healthcare system and several healthcare professionals would die while working in a high virus load environment.

Even with all our social distancing measures in place, we have a high death count that has brought healthcare system on the brink of overwhelm, in many places. In New York, a dense state with high international travel, there was a death count of almost 15,000 in a population of less than 10M. Healthcare professionals from several other geographical regions traveled to New York to lend help. Can you imagine every state taxed that way beyond their maximum capacity to care for the patients? And that is the reason that scientists and business leaders are not advocating herd immunity as an ultimate preventive measure. We can be lay people and choose to remain ignorant and spread the forwards and myths about herd immunity OR we can listen to what science has to say over what the politicians may be advocating.

Lessons from Shanghai, China: Strategy for containment & care during Covid-19

Recently, CABS, the Chinese American Biopharmaceutical Society hosted a webinar on the topic,  “COVID-19 Clinical Treatment and Research Experiences from China”, with Dr. Wenhong Zhang. Dr. Zhang is Director of the Department of Infectious Diseases in Shanghai and leader of Anti-Covid-19 team. He is also on Chinese Society of Infectious Disease and with Chinese Association of Internal Medicine. During the fight against Covid-19, Dr. Zhang led the Shanghai team to formulate a clinical treatment and containment plan.

 

An article in scientific publication Lancet predicted in late January that after Wuhan, Shanghai can be the epicenter of the virus with as many as 800,000 cases. However, with very early focus on containment and reasonable social distancing (even without complete lockdown measures), Shanghai managed to restrict the spread to about 4,000 cases. The key was that the healthcare system went on full alert when they had their very first case of a person traveling from Wuhan.

 

Dr. Zhang shared many details of their process for containing the spread and answered questions sent by the audience members. I have captured a few of the nuggets from his talk and I am sharing them below.

Diagnosis: Immediately they optimized diagnostics and did all needed tests for suspected patients. Shanghai made separate fever clinics and all patients who met 1 epidemiology criteria plus one clinical criteria were encouraged to go to these clinics. Suspected Covid-19 patients were sent to separate quarantine wards for full testing, and while they awaited results.  If the results came back positive, they were sent to separate hospitals for quarantine stay and were tested again, before release.

 

Further, while in the US some hospitals first tested for flu and other viruses and if the patient tested positive for any of them then they were not tested for coronavirus, Shanghai tested all suspect cases for coronavirus. Dr. Zhang said that they have found that there are a lot of co-infections so a person can have regular flu virus plus coronavirus. Additionally, they found a high negative rate in PCR testing, while a positive rate was around 70%. Therefore, despite negative test results, if the patient was highly suspect than they did more testing. They did not rely on CT scans because they found that a chest CT cannot precisely confirm Covid and all cases needed molecular diagnosis.

 

Detailed process in place: Shanghai had a very detailed process in place for the steps to be taken for patients in the first screen, then first test, then when tested positive, if tested negative, and for followup.  Timely diagnosis and timely distancing and quarantine is very important, said Dr. Zhang. Immediate separation and early control of local transmission is the key to stop the Covid-19 disease spread, said Dr. Zhang.  This is something that did not happen in Italy. Almost all of their early cases were of foreigners. Eventually all of their cases and high death toll has been among the local population.

 

Treatment Options: Dr. Zhang shared that over 95% of the patients recovered and eventually were released. One patient died. There has been debate around anti-viral treatments. Dr. Zhang said, these treatments don’t seem to be effective. China also used hydroxychloroquine (widely touted malaria drug) to treat Covid patients and did not find it to be effective. However, it can have compassionate use since it shows little lasting side effects, said Dr. Zhang. Although he did not observe clinical evidence of anticoagulants, he said, it is possible that early anticoagulation may block clotting and eventually reduce the risk of major organ damage.

 

Respiratory Treatment: Dr. Zhang shared that the most fundamental treatment in keeping patients alive is respiratory treatment. We have a narrow window to stop progression from mild symptoms to severe symptoms, said Dr. Zhang. Low and short duration corticosteroids may stop progression and we need more studies to find that out. Life support for critically ill patients is crucial. Timely intervention with mask oxygen inhalation, nasal cannula oxygen therapy, mechanical ventilation etc. can prolong life until the body’s immune system gets critical time to fight off the virus.

 

Medical Personnel: In Shanghai, strict following of protocol, translated into not a single infection spreading into the healthcare professionals. Highly qualified and standardized process included appropriate PPE (personal protective equipment) with gowns, goggles, masks, double layer gloves and shoe covers. Healthcare professionals were asked to never share a meal with others at home, during the time this contagion was active. As far as possible, the patients were kept in negative pressure wards and surfaces were cleaned with disinfectants every 4 hours.

My Comments
Stay tuned for my next article on how China effectively used high tech, specifically big data and coupled it with public awareness and public participation to contain the virus. Please note: I am not a fan of, or in any way endorsing communism or authoritarianism. And yet, perhaps there are lessons even for Western democracies, to pay heed to early signs and implement containment strategies. And that is exactly what Bill Gates was referring in 2015, when he spoke at TedTalks and warned us about a virus pandemic that can possibly kill millions. That is what various scientists have been warning of, for years.

Summit, IBM supercomputer is our recent hero in the fight against Covid-19

The looming threat of Covid-19 and the grim reality of the toll that novel coronavirus takes on humankind, makes it imperative that we find a way to prevent the spread faster and with less cost. Currently nine out of ten drug therapies fail mostly between phase 1 trials and regulatory approval. The estimated cost of developing a new treatment is around staggering US $2.6 billion.  While this article won’t address it, I want to mention that many bio/pharma companies are working with repurposed drugs to find a cure and at least 69 drugs have been identified as treatment possibilities. Drugs also have side effects and need to be tested for safety. Let us focus for a while on search for the vaccine.

Many companies including Moderna, CureVac and BioNTech are working on vaccines. With the help of  Machine Learning, Artificial Intelligence and other technologies the hunt for new pharmaceuticals and appropriate chemicals is expected to be quicker, cheaper and more effective. Novel coronavirus presents the most unprecedented challenge to date because of the speed with which it spreads. 

Who better than a supercomputer made by a company that has been on the cutting edge of innovation for over a century, to take on this speed challenge? IBM scientists instructed the world’s fastest computer to tackle this challenge at its Oak Ridge National Laboratory in Tennessee. Summit can run 200 quadrillion computations per second. The scientists ran thousands of simulations to analyse which drug compounds could stop the coronavirus from infecting the host cells. 

Summit, an IBM supercomputer equipped with the “brain of AI” identified 77 compounds (from over 8000 compounds) that could be efficacious in preventing coronavirus from spreading in the host.  This is promising news in humanity’s quest for an effective vaccine against the virus. These findings are published in the journal ChemRxiv and give us hope although road is still long to get there.

With increasing computer processing power and advanced algorithms, AI has been employed to analyze large data sets with greater efficiency and will likely lead to many exciting innovations.  While AI and ML show promise to change every industry sector for the better, artificial intelligence, machine learning and deep learning have become the most widely discussed topics in the healthcare sector and the excitement keeps growing.  

I will be looking forward to hearing about new innovations AI/ML at #TiEcon2020. Stay tuned for new dates for the conference at http://www.tiecon.org and on this blog.