Understanding the Concept of ‘Herd Immunity’

Niagara Falls (Dr. Noorali Bharwani)
Niagara Falls (Dr. Noorali Bharwani)

According to WHO website, ‘herd immunity’, also known as ‘population immunity’, is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached.

If 90 per cent of the population is vaccinated then the rest of the population is generally protected by the concept of herd immunity. Herd immunity is achieved by breaking the chain of transmission of the virus by immunization.

Important point is herd immunity is achieved by protecting people from a virus, not by exposing them to it.

Unfortunately, herd immunity cannot be achieved with COVID-19.

Currently, we do not have a vaccine against the virus. Vaccines train our immune systems to create proteins (antibodies) that fight disease, just as would happen when we are exposed to a disease. Vaccines work without making us sick.

The percentage of people who need to have antibodies in order to achieve herd immunity against a particular disease varies with each disease. For example, herd immunity against measles requires about 95 per cent of a population to be vaccinated. The remaining five per cent will be protected by the fact that measles will not spread among those who are vaccinated. For polio, the threshold is about 80 per cent, says WHO website.

There are two ways to herd immunity for COVID-19 – vaccines and infection.

Vaccines: Using the concept of herd immunity, vaccines have successfully controlled deadly contagious diseases such as smallpox, polio, diphtheria, rubella and many others. People who oppose vaccines do pose a real challenge to herd immunity.

Natural infection: Herd immunity can also be reached when a sufficient number of people in the population have recovered from a disease and have developed antibodies against future infection.

However, there are some major problems with relying on community infection to create herd immunity.

It isn’t yet clear if infection with the COVID-19 virus makes a person immune to future infection. Even if infection with the COVID-19 virus creates long-lasting immunity, a large number of people would have to become infected to reach the herd immunity threshold.

Experts estimate that in the U.S., 70 per cent of the population – more than 200 million people – would have to recover from COVID-19 to halt the epidemic. If many people become sick with COVID-19 at once, the health care system could quickly become overwhelmed. This amount of infection could also lead to serious complications and millions of deaths, especially among older people and those who have chronic conditions.

In most countries, less than 10 per cent of the population have been infected with COVID-19. It would be scientifically problematic and unethical to expose millions of people to the virus to achieve herd immunity. Letting COVID-19 spread through populations, of any age or health status will lead to unnecessary infections, suffering and death.

We are still learning about immunity to COVID-19. Most people who are infected with COVID-19 develop an immune response within the first few weeks, but we don’t know how strong or lasting that immune response is, or how it differs for different people. There have also been reports of people infected with COVID-19 for a second time.

Until we better understand COVID-19 immunity, it will not be possible to know how much of a population is immune and how long that immunity last for, let alone make future predictions.

It is crucial to slow the spread of COVID-19 virus and protect individuals at increased risk of severe illness. Wear a mask in public, maintain social distance, avoid big gatherings and wash your hands frequently.

Prevention is better than cure. If you have cough, fever, and difficulty breathing, seek medical care early.

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How to Lose Weight During the Pandemic

Golden Gate Bridge in San Francisco. (Dr. Noorali Bharwani)
Golden Gate Bridge in San Francisco. (Dr. Noorali Bharwani)

Are you overweight or obese? Easy way to find out is by measuring your height and girth. Your girth should be half the size of your height.

Studies have shown obesity is a significant factor for critical illness during COVID-19. Obesity was also an important factor for mortality in patients with COVID-19. This is most likely due to obese patients were known to have a defective immune system that makes them vulnerable to a type of infection that specifically require a prompt cellular immune response (Obes Res Clin Pract. 2020 July-August).

The current pandemic has changed people’s social life limiting outdoor activities. They gain weight. It is known as “Quarantine 15”. Many people have put on 15 or more pounds in weight during the last six months or so.

The weight gain is not a surprise if you have a sedentary lifestyle. With gyms closed and groceries delivered, it was easy to lounge around and eat. People working from home have additional stress of managing family and keeping up with work schedule. Binge eating, snacking and comfort eating was a psychologically verified response to stress.

Stress and depression are going to affect your weight. When you are under stress your body tries to protect you by not giving up any calories. Plus, you tend to eat more when you are depressed.

According to the Centers for Disease Control and Prevention (CDC), severe obesity increases the risk of a dangerous breathing problem called acute respiratory distress syndrome (ARDS), which is a serious complication of COVID-19.

Also, people with severe obesity are more likely to have other chronic diseases and health conditions that can increase the severity of COVID-19.

The immune response to infection is altered in overweight patients. We do not know how effective a COVID-19 vaccine will be for these individuals.

Losing five or 10 pounds during the pandemic is entirely possible. Weigh yourself at least once a week. People who weigh themselves are more likely to keep their weight down.

Dr. John Morton, MD, medical director of bariatric surgery at Yale New Haven Health System, says he has seen patients in telehealth appointments who have gained five, 10, and even 30 pounds during the pandemic (Yale Medicine, July 1, 2020). They are looking for ways to lose weight.

How to lose weight during the pandemic?

The first step is to come up with a plan, says Dr. Morton. He recommends building new routines around what he calls the four pillars for weight loss: diet, exercise, sleep, and stress management. You have to have a disciplined routine otherwise it does not work.

“That means getting up in the morning, taking a shower, getting breakfast, and having a plan for the day. Purpose gives direction, and it helps when it comes to weight,” says Dr. Martin.

One or two pounds a week is a reasonable weight loss pace, Dr. Morton says. “If you want to cut back by 500 calories a day, that might mean you are exercising the equivalent of 200 calories and cutting out 300 calories in your diet.” It can be done.

Where there is a will there is a way. Be safe and stay healthy.

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10 Lifestyle Changes to Survive COVID-19

Niagara Falls, Ontario. (Dr. Noorali Bharwani)
Niagara Falls, Ontario. (Dr. Noorali Bharwani)

“The new realities of working from home, temporary unemployment, home-schooling of children, and lack of physical contact with other family members, friends and colleagues take time to get used to. Adapting to lifestyle changes such as these, and managing the fear of contracting the virus and worry about people close to us who are particularly vulnerable, are challenging for all of us. They can be particularly difficult for people with mental health conditions,” says World Health Organisation.

Fortunately, we can do a lot to look after our own mental and physical health and to help others who may need some extra support and care.

Here is a list of 10 things you can do to keep yourself and your family safe, healthy and happy:

1. Fear of COVID-19. It is normal to be afraid of COVID-19. But if you follow the rules laid down by the health officers then you do reduce your risk of contracting the illness. It also helps keep your family stay healthy.

2. Loneliness, anxiety and depression. Loneliness is the state of mind. You can be in a company or relationship and you may feel lonely. You may be alone and feel sorry for yourself. It’s a feeling of sadness or even anxiety that occurs when you want company. Humans are social animals. Our connection to others enables us to survive and thrive. So, stay connected with your family and friends. Talk to them frequently and laugh with them.

3. Fear of fake news. Follow trusted news channels, such as local and national TV and radio. WHO website is another place to check for facts.

4. Maintain your daily routine. Early to bed, early to rise and go for a walk, go to a gym or workout at home.

5. Control your desire to eat. That is the best way to control your weight. If you are spending more time at home due to the pandemic then organize your eating routine. Avoid snaking in between meal times. Remember, it is easy to put on weight but very difficult to get rid of it.

6. Dangers of alcohol and drugs. Do not start drinking alcohol if you have not drunk alcohol before. Avoid using alcohol and drugs as a way of dealing with fear, anxiety, boredom and social isolation.

7. Support your children. Your children need your attention with at-home learning and make sure time is set aside for play. Help children find positive ways to express feelings such as fear and sadness. Sometimes engaging in a creative activity, such as playing or drawing, can help you with this process.

8. One for all, all for one. Each individual should act for the benefit of the group, and the group should act for the benefit of each individual. Even if we cannot be close physically, we need to stay close emotionally and reach out if someone needs support.

9. Protect yourself and protect others. Wearing a face mask is becoming mandatory in many places. You must also consistently and strictly adhere to good hygiene and public health measures, including frequent hand washing and physical (social) distancing.

10. Finally, have a sense of purpose in life. Make the best use of the time you have due to the circumstances beyond your control. Be in charge of your dreams and wishes. Never lose hope. Never give up. Tough times never last but tough people do.

Take care. Be safe. We can win this battle together.

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Use of high-dose influenza vaccine for seniors.

Sunrise in San Francisco. (Dr. Noorali Bharwani)
Sunrise in San Francisco. (Dr. Noorali Bharwani)

Our immune system changes as we get older. And flu season takes its toll. Use of high-dose influenza vaccine for people 65-years of age and older can have some benefits.

Canada’s flu season typically starts in October, when temperatures drop and people are in closer contact with each other indoors. The time to get a flu shot is between now and November, before the virus is circulating widely, says the Public Health Agency of Canada (PHAC) on its website.

As Canada braces for another flu season alongside COVID-19, experts say it’s difficult to predict the severity of the virus and the effectiveness of the flu shot this year.

How many Canadians are affected by the flu each year?

An estimated 3,500 Canadians die of the flu each year and 12,200 are hospitalized, making it one of the 10 leading causes of death in this country, says PHAC.

According to the national Influenza Vaccine Coverage Survey, we know that only 42 per cent of Canadian adults reported getting the flu shot last season, though it’s up from 38 per cent in the 2017-18 season and 36 per cent in 2016-17.

“Despite the fact that the influenza vaccine is much better than nothing… a lot of people still think that they don’t want to get it because it’s not good enough,” says Dr. Allison McGeer, a physician and infectious diseases specialist at Mount Sinai Hospital in Toronto (Second Opinion CBC Oct 12, 2019).

“Influenza vaccines are about 50 or 60 per cent effective in protecting you from hospitalization due to influenza. How good are seat belts at protecting you from dying in a car accident? About 50 per cent. How good are smoke detectors at reducing your risk of death in a house fire? About 35 per cent. So, we have this weird double standard that goes on with vaccines,” says Dr. McGeer.

There are two types of flu vaccines. The high-dose vaccines contain four times as much flu virus antigen – the part of the vaccine that stimulates the immune system – as regular Fluzone and other standard flu vaccines.

High-dose vaccines are meant for seniors. This can give older people a higher immune system response against the flu. Fluzone High-Dose is approved for use in Canada for adults 65 years of age and older. It costs about $75 and needs to be ordered in advance compared to regular Fluzone vaccine. There is no charge for the regular vaccine.

Fluzone High-Dose is given by injection. Like other flu vaccines, Fluzone High-Dose is made up of the three flu strains most likely to cause the flu during the upcoming flu season. A new vaccine called Fluzone High-Dose Quadrivalent that is made up of four flu strains has also been approved for people age 65 and older.

People age 65 and older have the highest risks of flu complications. Protecting this group from the flu is especially important.

Some older adults may have weaker immune systems, which can lead them to be less protected after a regular flu vaccine. In response to a regular flu shot, older people produce 50 per cent to 75 per cent fewer antibodies, which protect against the vaccine antigens, than do younger adults.

Studies have found higher antibody levels in older adults who received high-dose flu vaccines than in those who received standard flu vaccines.

In addition, one study found almost 25 per cent fewer cases of influenza in adults age 65 and older who took the high-dose vaccine compared with those who took the standard-dose vaccine.

In a large study comparing high-dose and standard-dose flu vaccines, those who received the high-dose vaccine were more likely to develop side effects during the week after getting the vaccine. Side effects included a fever and soreness at the injection site.

Canada’s National Advisory Committee on Immunization (NACI) concluded that Fluzone High-Dose vaccine for older adults should provide superior protection compared with our standard dose vaccine. It is 24.2 per cent more effective than regular Fluzone vaccine.

We are going to face many challenges this winter. So, make sure you get your flu shot as soon as it is available. Take care. Be safe. Protect yourself and protect others.

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