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Published on: Apr 20, 2020
3 minute read
By: Dr Rajan Choudhary

Is Herd Immunity A Valid Strategy For COVID 19?

Yesterday we explained you what Herd Immunity means and how it works, today we will take the discussion further to determine whether it is effective and can be recommended in the current context.

COVID-19 currently does not have a cure or a vaccine. Lockdown is the only strategy that appears to be working. Could implementing policies that encourages herd immunity be used to accelerate immunity in the population without the need for a vaccine?

INFECTIVITY

For the strategy to work we need to know a few things about the virus. How infective is it? In one of our earliest blogs we discussed infectivity at length and determined that the R0 (infectivity) may be between 2 and 3. This means each person with the virus can infect around 2-3 people at a time. Whilst this is not as high as Mumps (10-12) it is much higher than the common flu. The higher the R0 the more people that need to be immunised before herd immunity is achieved. For COVID it is estimated that 70% of the population need to be infected.

This is based off our current testing. Due to shortages in testing kits, only testing those that have a high likelihood of being infected and poorly organised testing infrastructure in some countries, we are likely underestimating. The number of people infected may be much higher as we are missing those that are asymptomatic but still have the disease and are still passing the disease on.

MORTALITY

Secondly, we need to know the mortality from COVID-19. Early estimates of mortality were as high as 10%, as we had little data on how many people were truly infected, but as the number of infected cases rose, and testing amongst the infected and symptomatic population rose, a more accurate mortality has been found to be around 1%. There is a risk we may still be underestimating the true mortality, as some cities have noted a spike in cardiac deaths, and some evidence supports possible cardiac damage due to COVID. But from the data we have, we know its mortality is lower than MERS (34%) and SARS (10%) but more than influenza (0.1%).

estimates of the COVID-19 case fatality rate

Whilst we have some data on who is likely to suffer from severe COVID symptoms (elderly, immunocompromised, people with heart or lung problems) we still cannot accurately determine who will get severe COVID in the “low risk” population. Simply because someone is young and healthy does not mean they will not die from COVID.

LENGTH OF IMMUNITY

Third we need to know how long this immunity will last. Similar coronaviruses responsible for the common cold usually create immunity that lasts for a few months, which is why we often get the cold repeatedly. A virus is also very prone to mutations that can change the structure and functions of its proteins, proteins responsible for tagging, latching on to and entering cells. If the structure of these proteins changes enough, then our antibodies will not be able to bind on, and new types of antibodies will have to be made with a slightly different structure. This effectively means our bodies have to start from step 1 again to create immunity, and we have to make new vaccines. This mutation rate is why we have to make new vaccines every season for the flu.

LONG TERM COMPLICATIONS

Finally, we need to know if there are any long-term implications from a viral infection. Again, this is something we do not know yet, as the virus has only been around for a few months. There may be implications for the cardiovascular system, long term breathing problems or more. And even if the complication rate appears relatively low (say, 1%), if millions of people are allowed to get infected, by definitions thousands or tens of thousands of people will have these complications, complications that can lead to issues later in life or an early death.

CONCLUSION

So, is herd immunity a viable strategy for COVID? Without a safe vaccine the general consensus appears to be no.

We don’t know how infective the virus really is or how many people it has infected

A 1% death rate is still very high. This means for every 100 people to be infected; one will die. This would mean hundreds of thousands of people dead in a country with a population over 10 million. It is unacceptably high.

If the death rate is 1%, then hospitalisation rate is likely higher. Almost all countries do not have capacity to have 1% of the population in hospital. Overwhelming the healthcare system will lead to poorer care, and worse care for those who do not have COVID. Leading to more people coming to serious harm or dying as a result of poor healthcare, not because of COVID.

We don’t know the long-term effects of COVID. By purposefully infecting people instead of waiting for a vaccine we may be causing unnecessary damage to a person’s health that only becomes apparent later in life. But this is speculation as we do not currently know if COVID has long term effects,

We don’t know if all of the risks above will amount to anything. The immunity may not last long enough, leading to another spike in infections and mortality.

Mass vaccination appears to be the safest strategy. And though human clinical trials have started on a number of vaccines, we are still months away from deployment. Until then we should not come out of lockdown prematurely, not until we have received an unbiased assessment from public health officials that states it is safe.

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Understanding Diabetes Type 2 Symptoms: A Simple Guide

Diabetes is a common health condition that affects millions of people around the world. Among its different types, Type 2 diabetes is the most widespread. It often develops slowly and can go unnoticed for years. That's why it’s important to understand the symptoms of diabetes type 2, so you can take timely action and protect your health.

In this blog, we will explain what Type 2 diabetes is, the signs to watch out for, and when to see a doctor.

What is Type 2 Diabetes?

Type 2 diabetes is a chronic condition where your body either doesn't produce enough insulin or can’t use it properly. Insulin is a hormone that helps your body control blood sugar (glucose) levels. Without enough insulin, sugar builds up in your bloodstream instead of being used for energy.

This buildup of sugar can damage your organs over time, including your heart, kidneys, eyes, and nerves. That’s why early detection and treatment are very important.

Who is at Risk?

Type 2 diabetes can affect anyone, but some people are more likely to get it. You may have a higher risk if you:

Are overweight or obese
Have a family history of diabetes
Are over the age of 45
Live a sedentary (inactive) lifestyle
Have high blood pressure or cholesterol
Had gestational diabetes during pregnancy
Belong to certain ethnic groups (such as South Asian, African-Caribbean, or Hispanic)

Knowing your risk factors can help you stay alert and get tested early.

Common Diabetes Type 2 Symptoms

The symptoms of Type 2 diabetes often develop slowly, and many people may not notice them right away. Some people don’t experience any symptoms at all until complications arise. That’s why it’s sometimes called a "silent" disease.

Here are the most common diabetes 2 symptoms to look out for:

1. Frequent Urination

If you find yourself needing to urinate more often than usual, especially at night, it could be a sign of high blood sugar. Your body tries to get rid of the excess glucose through urine.

2. Excessive Thirst

Frequent urination can make you lose a lot of water, leading to dehydration. This makes you feel unusually thirsty all the time.

3. Increased Hunger

Despite eating enough, people with Type 2 diabetes may feel hungry more often. This is because the body isn’t using the glucose in the blood properly for energy.

4. Fatigue and Tiredness

When your body can’t use sugar for fuel, it leads to low energy levels. This can make you feel tired, weak, or sluggish even after a good night's sleep.

5. Blurred Vision

High blood sugar levels can affect the tiny blood vessels in your eyes, leading to blurry vision. If untreated, it can even cause permanent eye damage.

6. Slow Healing Wounds

Cuts, bruises, or infections may take longer to heal if your blood sugar is high. This happens because diabetes affects blood circulation and the immune system.

7. Tingling or Numbness

Many people with diabetes experience tingling, pain, or numbness in their hands or feet. This is known as diabetic neuropathy and is caused by nerve damage due to high blood sugar.

8. Unexplained Weight Loss

If you're losing weight without trying, it could be a warning sign. When your body can’t use sugar properly, it starts burning fat and muscle for energy.

9. Skin Problems

Dark patches on the skin, especially around the neck or armpits (a condition called acanthosis nigricans), can be an early sign of insulin resistance.

When Should You See a Doctor?

If you notice any of the above symptoms, it’s important to see a healthcare provider for a simple blood sugar test. Early diagnosis can help you manage the condition better and prevent serious complications.

Even if you feel fine, it's a good idea to get regular health check-ups, especially if you’re at higher risk.

How is Type 2 Diabetes Diagnosed?

Doctors use the following tests to diagnose Type 2 diabetes:

Fasting blood sugar test: Measures blood sugar after not eating for 8 hours
HbA1c test: Shows your average blood sugar levels over the last 2-3 months
Oral glucose tolerance test: Measures how your body handles sugar after drinking a sweet drink
Random blood sugar test: Can be done at any time of the day

Your doctor may repeat tests or use more than one type to confirm the diagnosis.

Can Type 2 Diabetes be Managed?

Yes! Type 2 diabetes can be managed with lifestyle changes, medications, and regular monitoring. Some people are even able to reverse it through weight loss and healthy habits.

Here’s how you can manage it:

Eat a balanced diet: Include whole grains, vegetables, lean proteins, and fruits
Exercise regularly: Aim for at least 30 minutes of activity most days of the week
Lose excess weight: Even a small amount of weight loss can improve your blood sugar
Take medications if needed: Your doctor may prescribe tablets or insulin
Monitor blood sugar: Keep track of your glucose levels as advised by your doctor
Avoid smoking and alcohol: These can worsen diabetes and its complications

Final Thoughts

Type 2 diabetes is a serious condition, but it can be controlled and even reversed with the right steps. Understanding the early warning signs and diabetes 2 symptoms can make a big difference in your health journey.

If you or someone you love is experiencing these symptoms, don’t wait—talk to a doctor today and get tested. Early action can help you lead a healthier, longer life.

Take control of your health today—recognize the diabetes 2 symptoms early and consult your doctor for a proper diagnosis and care plan.