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Published on: Apr 19, 2020
3 minute read
By: Dr Rajan Choudhary

What Is Herd Immunity With Respect To Covid19 ?

Herd immunity: the basics

Many countries have been in lockdown for over a month, and some have tried to begin the discussion of an exit strategy. We know that remaining in lockdown continuously is not a feasible strategy, as many people have been suffering economic consequences from the stringent lockdown measures, and many countries have been providing significant monetary and fiscal support for people and businesses at risk. But leaving lockdown too early has its own consequences.

Almost all public health professionals will agree that the lockdown has been able to significantly reduce infection rates and reduce the pressure on our healthcare systems. By taking this early victory and prematurely ending lockdown we risk another wave of infections, reintroducing lockdown, and having an overall negative effect on the general health of the populous.

So what can we do? One exit strategy that has been touted recently is herd immunity. To understand how to may work for COVID we must understand what epidemiologists mean by herd immunity.

IMMUNITY

Our body’s immune system fights against invading organisms such as bacteria and viruses. For a more in-depth discussion you can have a look at previous blogs on Vaccines and Boosting the Immune system. The immune system is very competent and has mechanisms to theoretically recognise any protein tags that do not belong to that person’s cells, even protein tags that do not currently exist in nature. This gives the immune system the ability to theoretically recognise nearly any invading organism that has existed or will ever exist.

The immune system goes beyond this as well and produces “memory cells”. These remain in the blood after an infection for a long time; in some cases, it can even be lifelong. When a second infection occurs from the same organism the immune system jumps into action and is able to produce antibodies against the invader almost immediately. This can neutralise the invader before it has a chance to replicate, cause severe symptoms and harm the body. Sometimes we never realise we have been infected as the infection never gets a chance to cause any damage.

Importantly, if the invader cannot replicate in our body, then its ability to spread to other people is also reduced. For example, respiratory viruses can rapidly replicate in our lungs and be transmitted when we cough or sneeze. By eliminating the virus before it can replicate extensively the number of viral particles in each cough and sneeze is reduced, reducing the chances of another person catching the infection.

This is the basis of how vaccines work and is covered in depth in the two part blog.

HERD IMMUNITY

If our immune system is so competent, why do we need to worry about infections at all? Surely we can all get infected and gain immunity. In an ideal world where everyone was healthy this may be true. But there are many people who do not have fully functioning immune systems. These people are immunocompromised and can be for many reasons.

Chemotherapy and radiotherapy for cancer destroys rapidly dividing cells such as cancer cells. Unfortunately, it also hits other dividing cells, such as hair follicles, gut lining and the bone marrow, which produce the white blood cells that give us immunity. Chemotherapy patients are very susceptible to even the mildest of infections. Even if a mild infection is suspected, they are treated aggressively with antibiotics, as their lowered immune systems can become overwhelmed very quickly.
Sometimes doctors advise patients to take medication that purposefully dampens the immune system. This is necessary for transplant patients, where the host immune system attacks the donor organ as it does not belong to the host, or in autoimmune disorders, where the immune system attacks the host by mistakenly recognising it as an “invader”.
Taking steroids long term has a similar effect, and is used quite commonly for skin disorders, asthma, COPD, and other inflammatory conditions.
People with various chronic illnesses can have reduced immunity as a result of the illness. High sugar levels associated with poorly controlled diabetes can cause worsening organ function, including the immune system. These patients are more susceptible to infections.
Finally, some people do not have fully functioning or welldeveloped immune systems for a variety of reasons, inherited or acquired. As we get older, the immune system function decreases, and simple infections can be devastating.

In all of these cases the ability to recognise invading organisms, destroy them and form immunity is hampered. Vaccination, one way of inducing immunity without causing the person to suffer from a full-blown infection, can also be ineffective in these patients, and some vaccines can be dangerous if used incorrectly. So how do we protect these vulnerable patients?

HERD IMMUNITY

This is where we go back to the earlier point. Immunity in healthy people can reduce or even prevent the spread of infection from one person to another. The number of healthy people outnumber the number of vulnerable, immunocompromised ones. Therefore, if we induce immunity in most people, the infection will simply not spread to the vulnerable ones. We don’t have to immunise everyone, just enough to prevent transmission. This is called herd immunity. This is why we immunise everyone with flu vaccines even those that are healthy and will survive a full blown infection. Because by preventing these people from inadvertently spreading the flu, they will protect those that we cannot immunise.

Does herd immunity work? For most other diseases, yes. It depends on how the disease is spread, and how infective it is. For measles, you need to immunise 19 out of 20 people to achieve herd immunity, because it is so infective. But once herd immunity was achieved death rates were drastically reduced. With the advent of anti-vaccine campaigns, particularly against MMR, this herd immunity has been lost, and many vulnerable children (and adults) who do not have fully functioning immune systems are now contracting this virus and dying from a preventable disease.

It can be achieved for pandemics as well. Norway was able to achieve partial herd immunity to H1N1 (swine flu) through a vaccination program and natural immunity. Vaccines are the best method for achieving herd immunity without extremely high death rates. We have already covered the issues with making a vaccine, and why it takes such a long time, in our previous blog

From reading this blog you should now have an understanding of what herd immunity is, and why it is important in protecting those that are vulnerable to infections. In our next blog we will look at why herd immunity may not be the solution for COVID-19.

Dr Rajan Choudhary, UK, Chief Product Officer, Second Medic Inc

www.secondmedic.com

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The Rise of Telemedicine: Revolutionizing Healthcare

In today’s fast-paced world, convenience is key. From online shopping to digital banking, everything is just a click away. The healthcare industry is no exception to this digital revolution, with telemedicine emerging as a game-changer. This new wave of healthcare delivery has not only made medical consultations more accessible but also provided timely care to patients, especially in remote areas. In this blog, we will explore the rise of telemedicine, its benefits, challenges, and the role it plays in shaping the future of healthcare.

What is Telemedicine?

Telemedicine refers to the use of digital technology, such as video calls, phone calls, or messaging apps, to provide healthcare services remotely. Through telemedicine platforms, patients can consult with doctors, discuss symptoms, receive medical advice, and even get prescriptions – all without stepping out of their homes. While the concept of remote healthcare isn’t entirely new, it has gained significant traction in recent years due to advancements in technology and the widespread use of smartphones and internet connectivity.

The Growth of Telemedicine

The COVID-19 pandemic served as a major catalyst for the widespread adoption of telemedicine. With lockdowns and social distancing measures in place, many people were unable or reluctant to visit hospitals or clinics. As a result, healthcare providers turned to telemedicine as a safe and effective way to continue offering care to their patients.

However, even before the pandemic, telemedicine was growing. Factors such as a shortage of healthcare professionals, long waiting times, and the rising cost of healthcare made remote consultations an attractive option. According to a report by McKinsey, telehealth usage in the U.S. increased by 38 times from pre-pandemic levels. Globally, the telemedicine market is expected to grow at a compound annual growth rate (CAGR) of 25.8% from 2020 to 2027.

Benefits of Telemedicine

The rise of telemedicine has brought numerous benefits for both patients and healthcare providers:

1. Increased Access to Care

Telemedicine has made healthcare more accessible, especially for those living in rural or remote areas where access to healthcare facilities is limited. With just a smartphone and an internet connection, patients can connect with healthcare professionals from anywhere, breaking down geographical barriers.

2. Convenience and Time-Saving

For many people, visiting a doctor’s office involves time-consuming travel and long waits. Telemedicine eliminates the need for physical travel, allowing patients to schedule consultations at a time that suits them. This is particularly useful for those with busy schedules, elderly patients, or individuals with mobility issues.

3. Cost-Effective Healthcare

Telemedicine can be a more affordable option for both patients and healthcare providers. Remote consultations typically cost less than in-person visits, and patients save on transportation and other associated expenses. For healthcare providers, telemedicine can help reduce overhead costs by minimizing the need for physical office space and staffing.

4. Continuity of Care

Telemedicine helps patients stay connected with their healthcare providers even when face-to-face visits are not possible. This is particularly important for patients with chronic conditions who require regular monitoring and follow-ups. Remote consultations allow doctors to track their progress and adjust treatment plans without the need for frequent clinic visits.

5. Reduced Risk of Infections

During outbreaks of contagious diseases, such as COVID-19, visiting a hospital or clinic can increase the risk of infection. Telemedicine provides a safer alternative by allowing patients to receive care from the comfort of their homes, thus reducing the spread of diseases.

Challenges Facing Telemedicine

While telemedicine offers many benefits, it also comes with its fair share of challenges:

1. Technology Barriers

Not everyone has access to the internet or the necessary devices for telemedicine consultations. In rural or underserved communities, limited internet connectivity can hinder access to remote healthcare services. Additionally, older adults or those who are not tech-savvy may struggle to navigate telemedicine platforms.

2. Lack of Physical Examination

Telemedicine works well for consultations, but it cannot replace the need for physical examinations in certain cases. While doctors can provide advice based on a patient’s symptoms, there are limitations when it comes to diagnosing conditions that require hands-on assessments or lab tests.

3. Privacy and Security Concerns

Telemedicine relies on the transmission of personal health information over digital platforms. This raises concerns about data privacy and security. Patients need to be assured that their sensitive medical information is protected, and healthcare providers must comply with regulations like the Health Insurance Portability and Accountability Act (HIPAA) to safeguard patient data.

4. Reimbursement and Insurance Issues

In some regions, the reimbursement policies for telemedicine services are not well established. Patients may face difficulties in getting their telemedicine consultations covered by insurance, which can deter them from opting for remote healthcare. On the other hand, healthcare providers may also face challenges in billing for telemedicine services.

The Future of Telemedicine

As technology continues to advance, the future of telemedicine looks promising. With the development of artificial intelligence (AI), wearable health devices, and remote monitoring tools, telemedicine will become more sophisticated and capable of providing personalized care to patients. AI-powered chatbots, for example, could assist doctors in diagnosing conditions by analyzing symptoms and medical history.

Additionally, wearable devices like fitness trackers or smartwatches can monitor a patient’s vital signs in real-time and share the data with their healthcare provider. This continuous flow of information allows for more accurate diagnoses and timely interventions, reducing the need for emergency hospital visits.

Telemedicine in Specialized Care

Telemedicine is also expanding its reach into specialized fields of medicine. For example, telepsychiatry allows mental health professionals to provide counseling and therapy to patients remotely, making mental health services more accessible. Similarly, teledermatology enables dermatologists to diagnose and treat skin conditions by reviewing images sent by patients.

Another emerging trend is the use of telemedicine for post-operative care. Patients recovering from surgery can have follow-up consultations with their doctors without the need for an in-person visit, reducing the burden on both the patient and the healthcare system.

Conclusion

The rise of telemedicine is revolutionizing the way healthcare is delivered. By providing increased access to care, improving convenience, and offering cost-effective solutions, telemedicine is making healthcare more patient-centered and accessible. While challenges such as technology barriers and privacy concerns remain, the continued growth and innovation in telemedicine point towards a future where healthcare is more personalized, efficient, and readily available to all.

As we move forward, telemedicine will continue to play a vital role in bridging the gap between patients and healthcare providers, ensuring that quality care is just a click away.