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Expert comment on antibody tests for COVID-19

What do we know about the immune response to COVID-19 and how does this differ by age, gender, co-morbidities or other traits? What are the different tests available? How reliable are they? Do the tests show immunity? And do we even know how long immunity to COVID-19 might last.

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Photo by Martin Sanchez from Unsplash.com

By Professor Georgina Ellison-Hughes, Dr Rocio Martinez-Nunez and Dr Rui Ribeiro Galao
Faculty of Life Sciences & Medicine
King’s College London

With promises of antibody tests being rolled out in the next few days, and retailers told not to send home-testing kits as their accuracy is questioned, it is timely to consider what we do and don’t know about these tests. What do we know about the immune response to COVID-19 and how does this differ by age, gender, co-morbidities or other traits? What are the different tests available?  How reliable are they? Do the tests show immunity? And do we even know how long immunity to COVID-19 might last.

What do we know about the immune response to COVID-19?

The immune response to COVID19 can be split into a healthy antiviral immune response or a defective/overactive immune response, which is often implicated in the resulting damage to the lungs and other organs, and then the person can be severely ill. There is a high percentage of patients that get infected with SARS-CoV-2 and do not develop any symptoms, hence the importance of social distancing to protect others since we do not know who can be carrying the virus.

Initially, viral infection switches on antiviral defences. These include interferons and pro-inflammatory cytokines and chemokines, which kill the virus and attract immune cells (neutrophils, monocytes, macrophages and T cells) to the site of infection. The virus enters cells employing ACE2 as a receptor, a protein that is expressed in many cell types and present in the epithelium in the airways.

In the healthy immune response, the innate antiviral defences fight against the virus and virus-specific T cells can later eliminate the infected cells before the virus spreads. Neutralizing antibodies in these individuals can block viral infection, and phagocytic cells such as alveolar macrophages recognize neutralized viruses and apoptotic cells and clear them by phagocytosis. Altogether, these processes lead to clearance of the virus and minimal lung damage, resulting in recovery.

In a defective immune response, there is a hyperactivation of the immune cells in the lungs causing overproduction of pro-inflammatory cytokines (cytokine storm), which eventually damages the lungs. The resulting cytokine storm circulates to other organs, leading to multiple organ damage. 

In patients that are severely ill there is a combination of multi-organ damage, increased coagulation and lymphopenia. Researchers are trying to elucidate the mechanisms underlying these responses and the causes for the hyperactivation of the immune response.

Longer-term immunity is acquired through antibodies made by the B cells of the immune system, which stick around in the blood post-infection. These antibodies can bind to the virus, either neutralizing it directly or marking it for destruction by other immune cells. Studies have found high levels of neutralizing antibodies to SARS-CoV-2 in recently recovered patients. This is the principle behind new trials such as those at Guy’s and St Thomas’ Hospitals in which severely ill patients receive plasma from recovered donors. Memory T cells are another source of long lasting immunity and are generated when a person gets infected, remaining in the blood and responding rapidly when re-infection occurs.

How does the immune response differ by age, gender, co-morbidities and other traits?

As we have observed, everyone responds differently to the virus with most healthy, infected people under the age of 65 making a full recovery. However, there is increased severity with age, and if you have an underlying health condition i.e. cardiovascular disease or diabetes. Black and ethnic minorities also seem more affected.

A retrospective, multicentre cohort study has shown old age, being male and cardiovascular disease co-morbidity are risk factors for mortality of COVID19 (Zhou et al. 2020, The Lancet). The most common cardiovascular co-morbidity as a risk factor for mortality is hypertension, followed by diabetes. Moreover, prevalence of hypertension is highest in the elderly population and advanced age remains the strongest predictor of COVID-19 related death.

Because disease severity is due to not only the viral infection but also the host response, older individuals suffer because they have a progressive decline in immune function with increasing age, called immunosenescence.

Another risk factor to disease severity and dying from COVID19 is being male. The reasons for this are currently unclear, but it has been suggested that women may naturally have stronger immune defences than men. Another possibility is that comorbidities associated with poorer prognosis are more common in men.

What are the various antibody test being trialled in labs, and being sold to the public? 

With no ‘gold standard’ for antibody testing and an incomplete knowledge of the immunology of COVID-19, it has been problematic to evaluate serologic tests. Several lateral flow immunoassays (similar to a pregnancy test) were initially trialled, with ease of use and affordability weighing heavily in their favour. Several of these have presented high sensitivities and specificities and are available to buy by the public (companies such as Alpha and Blue Horizon). The kits manufactured by Roche and Abbott will shortly be available on the NHS. There is a drive now to test different ELISA platforms including Abbott. ELISA takes longer than lateral flow tests but is quite reliable and is the preferred option for large scale testing.

What are the different ways you administer these tests? 

These are all blood tests, and most of them just use a finger prick of blood. The Roche and Abbott tests must be carried out by a doctor and the blood is sent to a laboratory for evaluation. The most commonly used method is to take a blood sample, spin it down in a centrifuge to obtain the plasma serum content of the blood and analyse the presence of antibodies, including neutralising antibodies. Saliva may be another source for antibodies.

Will the antibody test show that the person is immune? 

The test will detect whether you have the antibodies (immunoglobulins, IgG and IgM) against SARS-CoV-2. However, having antibodies does not automatically mean you are ‘immune’ against SARS-CoV-2. Neutralizing antibodies are more ‘effective’ against SARS-CoV-2 and most commercial tests detect only if there is presence/absence of immunoglobulins (Ig).

How reliable are the various tests?

The reliability can differ depending on what Ig’s are being detected and how long after you perform the test following testing positive for SARS-Cov-2. The antibody tests available are those that detect the presence of IgM and/or IgG and inform about current (likely in the case of IgM) or previous (IgG) infection with SARS-CoV-2. However, to determine presence of SARS-CoV-2, i.e. if a person is ‘infectious’, PCR remains as the gold standard.

Roche and Abbott have said the level of accuracy for its SARS-Cov-2 antibody test is high, and it was able to distinguish the antibodies from those for closely related coronaviruses, which have been known to produce positive results in tests made by other companies.

What are IgM and IgG antibodies and how do they affect the interpretation of the test?

Immunoglobulin M (IgM) antibodies are usually the first antibody produced by the immune system when a pathogen attacks. A positive IgM test indicates that you may have been infected recently (peaking at day 7-10 post-infection) and that your immune system has started responding to the virus.  When IgM is detected you may or may not still be infected.

Immunoglobulin G (IgG) antibodies develop in most patients within 7 to 10 days after symptoms of COVID-19 begin. IgG antibodies remain in the blood after an infection has passed. These antibodies indicate that you may have had COVID-19 in the recent past and have developed antibodies that may protect you from future infection. Therefore, an IgG antibody test is most reliable as a source of information about previous infection. Tests that combine measurement of IgM and IgG, and therefore do not distinguish between the two, cannot guarantee the presence of IgG antibodies, which are the ones that in theory confer longer immunity and remain in the bloodstream to protect from future infections.

How long does immunity last for?

In patients at least 14 days after discharge from hospital, studies show have high levels of antibody which suggests that their immune system is armed against further attack. Because SARS-CoV-2 has only been around for 6 months, how long the immunity lasts for is unclear. However, if SARS-CoV-2 is like other coronaviruses, like 2002’s SARS 1, or 2012 MERS, then immunity could last for several years. We think that we should err on the side caution because a recent study, by the group of Professor Lia van der Hoek from the University of Amsterdam tested 10 male individuals regularly over a time span of 35 years for four types of coronaviruses, which cause the common cold. Results showed an alarmingly short duration of protective immunity with frequent reinfections at 12 months post-infection and a substantial reduction in antibody levels as soon as 6 months post-infection. It is of note that respiratory viruses are not great at triggering long-lasting immunity.

Believing that everyone's perspective is important, Zest Magazine has opted to provide an avenue for these perspectives to be known. care to hear the publication's contributing writers; or better yet, do some contributing yourself by contacting info@zestmag.com.

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Daily ritual you’ll never want to skip for a healthier, happier you

As time passes by, we see our commitment to staying healthy weaken. It’s either we find ourselves making excuses to skip our workout routines, we forget to take our supplements, or we just eat whatever’s readily available without regard to its nutrition.

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Everybody dreams of having an active and healthy lifestyle. We all want to live long enough to reach all our goals and not be a burden to our families. However, in a fast-paced society, it is easy to get caught with the demands of our everyday life. Often, we juggle different roles such as that of a child, a parent, a friend, a partner, or even a workmate that require us to manage multiple responsibilities at once. As time passes by, we see our commitment to staying healthy weaken. It’s either we find ourselves making excuses to skip our workout routines, we forget to take our supplements, or we just eat whatever’s readily available without regard to its nutrition.

Then one day, we suddenly feel random parts of our body begin to ache, we easily get fatigued, and we can no longer do activities that we did with ease a year ago. This is when we realize that something needs to change with how we manage our lifestyle. But where do we start? How do we squeeze in staying healthy amidst our busy schedules?

If we want to become conscious of our health and what goes into our body, we need to be well-versed with what nutrients our body needs and how much of them we must consume to reach peak performance. It is important to take note that these essential nutrients are necessary for normal body function, growth, and development. However, they are not synthesized by our system, thus, they need to be externally sourced from foods or supplements.

The Macros

Macronutrients are the set of nutrients our body needs to consume in large amounts, specifically proteins, carbohydrates, and fats. These are broken down to provide energy and building blocks for our body’s structure.

Proteins are known as the body’s building blocks, especially for muscle tissue. They are also known to aid in our digestive system through digestive enzymes, improve the structure of our skin by providing antioxidants, collagen, and elastin, and nourish our hair and nails through keratin. Proteins can be sourced from lean meats, poultry, eggs, fish, and dairy.  

Another set of nutrients that our body needs in large quantities are carbohydrates or the body’s go-to energy source. They fuel us throughout our daily activities and during short to moderate lengths of exercise. Carbohydrates are the preferred fuel source for movement, biosynthesis of proteins, brain function, and more. This food group includes bread, pasta, rice, cereal, fruits, and vegetables.
The last set of essential macronutrients is healthy fats which are essential in giving the body energy and supporting cell function. They also help protect our organs and keep our body warm. We can get this from avocado, almonds, nuts, fish, and oils coming from olive, sunflower, and canola.

The Micros

Micronutrients are the set of nutrients that our body needs in smaller amounts but are nevertheless essential to our health. These are minerals and vitamins which are vital in ensuring that our bones, muscles, heart, and brain function properly and efficiently. These are also in charge of making enzymes and hormones. There are various sources for these like fruits and vegetables, lean meats, fish, whole grains, dairy, legumes, nuts, and liver.

The Supplements

But the thing is, it is not every day that we get to cook or consume meals containing all the essential nutrients that we must take in. Our body’s health needs remain constant day by day. So, what do we do? This is where supplements come in. They ensure that we still get the right amount of nutritional supply to eat, sleep, and perform better even on days our diet is insufficient.
This is something USANA is known for. Throughout the years, they took pride in providing consumers with the highest quality nutritional products to provide support in their active lifestyle. Their wide range of food supplements for various lifestyles and ages ensure that necessary support is provided where it is needed. Such supplements include: Cellsentials, MagneCal D, and BiOmega.

Maintaining a healthy lifestyle is a lifelong commitment. But it doesn’t have to be a burden as we go through our daily routines. Knowing the right nutrients and supplements and incorporating them in our daily ritual, a long and healthy life no longer needs to be just a dream but rather a lived reality.

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8 Ways to save on holiday expenses

Consider these tips from the money-saving experts at Slickdeals and Head of Deals Vitaly Pecharsky to avoid overspending without sacrificing your festive spirit.

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While often regarded as the most wonderful time of year, the holiday season is also an expensive spot on the calendar. Even as many families feel the squeeze of inflation and rising costs, there is hope for your budget when it comes to gatherings, gifts, food and beyond.

Consider these tips from the money-saving experts at Slickdeals and Head of Deals Vitaly Pecharsky to avoid overspending without sacrificing your festive spirit.

Stick to a budget. Beyond gifts and stocking stuffers, holiday costs can add up quickly once you factor in travel, decor, pet care, special events and more. Create an all-encompassing budget for the season then break it into segments for each type of expense, including hidden expenses like wrapping paper or extra toiletries for guests, so you don’t end up with an unexpected credit card bill.

Split up food costs. Instead of putting yourself under the pressure of full-time holiday chef (and taking on all the expenses that come with it), consider hosting a potluck-style gathering. Providing the main course and encouraging guests to bring an appetizer, side or dessert is an easy way to avoid a hefty hosting bill. Send an e-vite with a list of must-haves that allows loved ones to sign up for specific dishes to ensure everything is covered without doubling up.

Search for the best deals. Whether you’re looking for the perfect gift from toys to technology or trying to save on travel costs and home decor, make sure you find the best price. Consider sites where a community of millions of people work together to save money so you can be confident you’re getting the best deal. With 12 million shoppers assisting others by vetting and voting up the top deals from renowned retailers, your holiday needs are covered without sacrificing quality. You can also set Deal Alerts that send notifications directly to your inbox when a deal that matches your criteria is posted to the site.

Share experiences, not just “things.” Gadgets and gizmos may come to mind when brainstorming holiday gift ideas but remember some family members and friends just want more time together. If you’re considering a special experience for – and with – that special someone, think about their favorite hobbies and activities. Animal lovers may be overjoyed with a day at the local zoo and gearheads would cherish tickets to the next auto show. Integrating experiences into your gifting repertoire often makes for a more memorable (and cheaper) solution.

Take advantage of gift cards. A quick internet search can lead you to discounted gift cards, allowing you to save cash on holiday purchases. Or, for the one on your list who has everything, simply give the card as a gift so he or she can pick out what’s truly needed. As an added bonus, discounted gift cards are typically available even at the last minute so procrastinators can still save.

Show off your DIY skills. Buying new holiday decorations and replacing worn out crafts are seasonal expenses you may not immediately factor into your budget. Rather than heading to the store for (likely overpriced) ornaments and tablescapes, put your creative cap on and repurpose goods from around the house. Reusing items like glass jars to make homemade snow globes, for example, can be a crafty way to save. Plus, it’s a fun activity for family members to enjoy together.

Seek out post-holiday sales. Once the holidays are over, it’s a perfect opportunity to get ahead of the game for next year. Stock up on gift wrap, decorative items and other nonperishables that are often heavily discounted in the new year.

Save throughout the year. A handy tip for holiday seasons to come, try creating a fund each year where you can save up for gifts, food, travel and other end-of-year expenses. Set up a special bank account specifically for holiday savings where you contribute a small amount each month to be financially prepared for the festivities.

Find more ways to save this holiday season by visiting Slickdeals.com.

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Ways to protect your family from tornadoes

Keep your loved ones safe with these tips to prepare for and shelter from tornadoes.

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When clouds loom overhead and winds pick up in your area, it’s crucial to keep an eye on the sky and an ear toward local news broadcasts. Capable of destroying buildings, uprooting trees and sending dangerous debris flying, tornadoes are rotating columns of air that extend from the base of thunderstorms to the ground.

With the potential to reach wind speeds of up to 300 miles per hour, these violent storms can wreak havoc on communities and put families in danger. Keep your loved ones safe with these tips to prepare for and shelter from tornadoes.

Pay Attention to Weather Forecasts

Staying weather alert is always a good idea, particularly as strong thunderstorms build and approach your location. Check the forecast regularly to understand the risk for severe weather and, if possible, sign up for smartphone alerts or notifications.

Put a Plan in Place

Each member of your family should understand what to do in an emergency situation. Create a plan that includes where to shelter in the event of a tornado warning. Typically, this is a basement, storm cellar or interior room on the lowest floor of the home with no windows. If you have a safe room or storm shelter, which is a hardened structure designed to provide near-absolute protection in extreme weather events like tornadoes and hurricanes, this is the time to utilize it. Clearly define who is expected to gather emergency materials, such as flashlights, blankets, a first-aid kit and extra food and water.

Understand Watches vs. Warnings

Key phrases from sources like the National Weather Service include “tornado watch” and “tornado warning.” Make sure you understand the differences to react appropriately.

  • Tornado Watch: Tornadoes are possible in or near your location. Review emergency plans with loved ones and be ready to act quickly if a warning is issued.
  • Tornado Warning: A tornado is active according to sightings or weather radar. It’s time to take action and follow your family’s safety plan.

Build Your Home with Resistant Materials

If constructing a new home is on the horizon, consider the benefits of building with durable materials like insulated concrete forms (ICFs), which are a more resilient alternative to wood framing. For areas prone to natural disasters, ICF walls from Nudura provide superior strength to withstand extreme wind and impact damage from tornadoes and hurricanes. They also protect against wildfires due to a fire protection rating of up to four hours, compared to 45 minutes for wood framing, and provide greater comfort, durability and lower life cycle costs compared to wood structures.

Shelter Safely

When a tornado warning is in effect, acting quickly is crucial. If at home, head to the basement, safe room or interior room away from windows and, if possible, stay tuned to local news for updates. At school or the workplace, follow the guidelines in place from tornado drills and proceed calmly but quickly to the shelter location. If driving and unable to get to shelter, pull over and get down in your vehicle with your head covered or leave your car and seek shelter in a low-lying ditch or ravine.

Find more ways to protect your family from natural disasters HERE.

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