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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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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.

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Dad tips we take for granted but go a long way

With all the pressure that comes with responsibilities, dads also need to look after their own wellbeing too.



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There is no one-size-fits all way to being a father, but most working dads want to do the best to support their loved ones. With all the pressure that comes with these responsibilities, dads also need to look after their own wellbeing too. 

Donato Avellana is the Health and Wellbeing Lead for the Vibe Team at Canva Philippines, and as a father himself, he acknowledges the importance of work-life balance. He has helped build programs at Canva that empower employees to have a healthy work-life balance, with holistic programs for all domains of wellness. Taking his learnings from this, he shares some helpful and practical tips to help dads to develop healthy habits that can boost their happiness at work and at home. 

1. Rest and recover well

Rest and relaxation is crucial to improve our overall health. Try your best to get at least 7 hours of sleep, go to bed an hour before you go to sleep, and stay away from your TV or mobile phone, as several studies show that the blue light from screens can disrupt sleep. Sleep is often a neglected component of overall well-being, but this is where the body repairs itself to get ready for another day. Remember that you deserve to rest.

2. Start your day with a cold shower 

Showering can also offer more benefits than many realise.  By using water that is a little cold, you can improve blood circulation, with the lower temperature causing blood to run to the skin’s surface. Good blood circulation plays an important role in our health for proper nutrient distribution throughout our body.

This is also a good time for dads to have their ‘me’ time. Breathing exercises are a great way to start the day, by offering the opportunity to regroup and reflect. 

3. Move more, make it a habit

The health benefits of movement have been scientifically proven time and time again. Your body is connected to your brain and your movement habits can positively impact how you think and feel. Inactivity can make you feel sluggish and tired, making it hard to find motivation and deliver on responsibilities.

Add regular walks, stand often, or follow stretching routines that you can commit to during the day. Taking time for a short 10-15-minute walk is a great way to have a mental and physical break.

4. Eat smart: practice a mindful eating habit. 

We have been educated about what healthy eating is since we were kids. Eating intuitively on a regular schedule is very important. Eating with no structure creates mindless eating that can lead to poor nutrition choices. Think of nourishing your body with healthy fuel for efficient performance instead of just eating. Eat a variety of whole foods, have fruits and vegetables, and hydrate smartly.

5. It’s okay to ask for help

This shortlist might not be easy for everyone, so I encourage dads to seek help when they need it. You might want to start at home with your spouse, ask for help from co-workers, peers, fellow fathers, professionals such as your doctor.

Showing appreciation to your father

If you’re still looking for heart-felt gift ideas for your dad, you can browse through Canva for free design ideas and inspiration. 

Make your dad, grandfather or any other special figure feel loved and appreciated by designing personalized cards. A wide variety of photos, customizable templates, and full-color professional layouts are available. You can also find Filipino templates by changing the language settings to Tagalog and searching for the word ‘tatay’.

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Food safety when eating outdoors

Follow the tips below to keep your food safe when eating outdoors.



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June 20th marks the official start of summer, which means warm, sunny days perfect for picnics and barbecues.  Unfortunately, this time of year is also a favorite for foodborne bacteria that cause foodborne illness (also known as food poisoning), which multiply faster at temperatures between 40°F and 140°F. 

Follow the tips below to keep your food safe when eating outdoors.

Before your picnic

  • Defrost meat, poultry, and seafood in the refrigerator or by submerging sealed packages in cold water. You can also microwave-defrost, but only if the food will be grilled immediately afterward.
  • Never reuse marinade that touched raw foods unless you boil it first or set some of the marinade aside before marinating food to use for sauce later.
  • Marinate foods in the fridge, not the countertop.
  • Wash all produce before eating, even if you plan to peel it. The knife you use to peel it can carry bacteria into the part you eat. Fruits and vegetables that are pre-cut or peeled should be refrigerated or kept on ice to maintain quality and safety.
  • If your picnic site doesn’t offer clean water access, bring water and soap or pack moist disposable towelettes for cleaning surfaces and hands.
  • Don’t forget to pack a food thermometer!

Packing coolers

  • Place food from the refrigerator directly into an insulated cooler immediately before leaving home.
  • Use ice or ice packs to keep your cooler at 40 °F or below.
  • Pack raw meat, poultry, and seafood in a separate cooler, or wrap it securely and store at the bottom of the cooler where the juices can’t drip onto other foods. Place beverages in a separate cooler; this will offer easy drink access while keeping perishable food coolers closed.
  • Avoid loading coolers in the trunk of the car, as it can collect heat. Once at the picnic site, keep food in coolers until serving time (out of direct sun) and avoid opening the lids often.


  • Have clean utensils and platters available. Cook meat, poultry, and seafood to the right temperatures ─ use a food thermometer to be sure (see Safe Minimum Cooking Temperatures Chart). Keep cooked meats hot at 140 °F or warmer until serving time — set them to the side of the grill rack to keep them hot.
  • When removing foods from the grill, place them on a clean platter. Never use the same platter and utensils for cooked food that you used for raw meat, poultry, or seafood.

Time and temperature 

Don’t let hot or cold food sit in the “Danger Zone” (between 40 °F and 140 °F) for more than 2 hours – or 1 hour if the outdoor temperature is above 90 °F. If they do, throw them away.

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5 Tips to promote health during spring

Take steps this spring to ease the impact of sinus and allergy problems and focus on your overall wellness for a smooth transition with these tips.



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As seasons change, there’s often a great deal of shuffling and movement, including common allergy triggers like trees, pollen, mold spores, dust and dander along with pesky sinus pressure. Combined with changes in barometric pressure and weather patterns bouncing up and down, spring can be one big pain – literally.

“This is the time of year when most of us are excited to see the change of seasons, but millions of allergy and sinus sufferers welcome spring with trepidation,” Dr. Ian Smith, M.D., said. “Common triggers such as trees, pollen, mold spores, dust and dander can wreak havoc for many. Having a trusted multi-symptom reliever of upper respiratory allergies… is absolutely key in making the season more enjoyable for all suffering from sinus and congestion issues. With a reliable multi-symptom product stashed in your medicine cabinet, and the combination of simple modifications like being mindful of your indoor climate, eating more fruits and veggies, and staying hydrated, can help limit sinus discomfort this season.” 

Take steps this spring to ease the impact of sinus and allergy problems and focus on your overall wellness for a smooth transition with these tips:

1. Control your allergy and sinus triggers. 

Knowing what flares your allergic reactions can help prevent discomfort. For many people, monitoring pollen counts and limiting time outdoors on high-pollen days can help reduce reactions. You might also avoid hanging laundry outside, as pollen can stick to clothes and sheets as they dry, and ask for help with yardwork to limit your exposure.

2. Find some pressure release. 

When nasal congestion or sinus pressure build, it can feel like a ton of bricks have landed on your head. However, you can find relief with products designed to help clear up your stuffy nose, relieve headaches and thin and loosen excess mucus. Often, if you’re experiencing sinus problems, you’re dealing with multiple symptoms. From congestion to headaches and sinus pressure, an over-the-counter medicine like Mucinex Sinus-Max can break up your sinus symptoms with just one dose or your money back.

3. Manage your indoor climate. 

Even when you start spending more time outdoors, it’s important to keep close tabs on the quality of the air inside your home. If you’re prone to allergy flare-ups or sinus infections, manage the humidity level by using a humidifier or dehumidifier. If outdoor allergens are a concern, avoid opening windows and doors, and instead rely on air conditioning on warmer days. Also be sure to change filters regularly and use an air purifier for added protection.

4. Keep fluids flowing. 

More time outdoors in warmer weather can quickly lead to dehydration, especially if you’re working up a sweat. Drink plenty of water to stay well hydrated and keep your body operating in top shape. Staying hydrated can also help keep mucus moving, allowing you to ease through allergy or sinus problems.

5. Update your medicine cabinet. 

A seasonal change is a good time to take stock of your medical supplies and medications to ensure you have what you need for the months ahead. Discard any expired prescriptions or over the counter medicines and be sure restock common spring and summer essentials like bug bite ointments, sunburn spray and multi-symptom products like Mucinex Sinus-Max to help temporarily relieve sinus and congestion symptoms in one dose. Also be sure to replenish your first aid kit with plenty of bandages and wound care supplies.

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