Vaccinated Canadians can have COVID-19 symptoms despite testing negative. Experts say people can test negative on a rapid test in the first few days they have symptoms. This is partly due to how quickly vaccination clears the amount of the virus in an infected person’s body, the amount of immunity a person has built up. How much of the virus a person can spread to others and how serious a person’s disease is, are all dependent on the viral load, which is the amount of virus a person has in their system. Antigen rapid tests pick up on a higher viral load much quicker.

If the antigen test is dependent on the amount of virus in your upper respiratory tract, you may still be infectious in the first few days. There’s a period of around two days before the rapid test begins to pick up the antigen This is one reason why it’s always good to give a second rapid test, a day or two afterward, just to make sure it’s really negative.

The real problem is that between 40 to 70 % of people who carry COVID-19 do not have any symptoms at all. This means people who are carriers of the virus may not be getting tested at all because they don’t have any symptoms and don’t think they have COVID-19; if they do happen to get tested, it’s often negative.

If a rapid antigen test is positive, it’s reliable. If it’s not positive and you have symptoms compatible with COVID, you should be managing yourself and the people around you as if you are COVID-positive.

Fourth shots (Second Booster) of COVID-19 vaccines begin Thursday in Ontario for age 60 and up and for First Nations, Métis and Inuit over 18. Canada’s National Advisory Committee on Immunization (NACI) is now strongly recommending the “rapid deployment” of second COVID-19 booster shots for seniors over 80. The recommended interval between third and fourth shots is five months, but that a shorter interval may be warranted in some individuals. There’s no clear-cut answer on whether to rush out for one. I would advise older persons to get another booster right away because of the higher level of protection.

COVID-19 has had a really disproportionate impact on people 65 and older. One in 100 older people are not with us today who were with us before the pandemic because of COVID-19.

For younger, healthier people, it might make sense to boost in late summer so it reaches maximum efficacy in the fall. Vaccine efficacy wanes over time, so getting a booster now means you won’t have maximum protection in six or seven months. It might make sense to plan your booster around respiratory pathogen season in the fall, when cases of COVID tend to go up. If you’re younger, healthy and in a place where the virus circulation is very low, it’s less critical, but if you’re somewhere where infections are raging, or if you’re traveling, it makes sense to do it now. Multiple studies have shown that the older you are, the bigger the benefit from getting another booster.

On January 17, 2022, the oral antiviral Paxlovid was approved by Health Canada. Ontario has received limited quantities from the federal government.

Treatment with Paxlovid must begin within five days of symptom onset to be effective. A full course of treatment is three pills twice daily for five days in a row.

Ontario is prioritizing patients for treatment who have COVID-19 with the highest risk of severe outcomes, including:
immunocompromised individuals (PDF) aged 18 and over regardless of vaccine status
unvaccinated individuals aged 60 and over
unvaccinated First Nation, Inuit and Métis individuals aged 50 and over
unvaccinated individuals aged 50 and over with one or more risk factors (PDF)
You must also have a positive COVID-19 test to receive treatment.
If you think you may be eligible to receive Paxlovid, you can:
contact your primary care provider
call Telehealth Ontario at 1-866-797-0000
visit a COVID-19 Clinical Assessment Centre
If you have one of more of the following moderate to severe symptoms you should immediately call 911 or go to the emergency department:
severe difficulty breathing (struggling for each breath, can only speak in single words)
severe chest pain (constant tightness or crushing sensation)
feeling confused or unsure of where you are losing consciousness.

BA.2, the ‘Stealth’ Omicron subvariant, is now driving most coronavirus cases around the world. It’s not really new. Scientists first discovered the Omicron variant in November. The viral lineage already existed as three genetically distinct varieties with their own set of unique mutations. BA.2 was nicknamed the “stealth variant” when scientists had a difficult time tracking it on P.C.R. tests. Now that Delta has gone from dominant to rare, it’s easy to distinguish the two versions of Omicron on a P.C.R. test. Viruses that test positive for only two genes are BA.1, and those that test positive on all three are BA.2.

It seems to be easier to catch. Recently BA.2 has spread even faster than BA.1. Existing vaccines work against the BA.2 variant. Not always from catching it but from severe disease, especially those who received a booster. Vaccines remain highly effective against hospitalizations. BA.2 does not appear to be more severe than the previous version of Omicron. It is highly transmissible, but an individual infection was, on average, less likely to lead to a serious case of Covid than infections from Delta. Some authorized medications work against BA.2. Others don’t. Like BA.1, BA.2 is able to evade most monoclonal antibody treatments, making them ineffective. Some treatments, such as Evusheld and antiviral drugs Paxlovid, molnupiravir and remdesivir all remain highly effective against both BA.1 and BA.2 if taken soon after a positive test.

On March 17th, Health Canada authorized the use of the Moderna Spikevax COVID-19 vaccine in children 6 to 11 years of age. This vaccine was previously authorized for use in patients 12 years of age and older. NACI recommends that a complete series with an mRNA COVID-19 vaccine should be offered to children in the authorized age groups without contraindications to the vaccine, with a dosing interval of at least 8 weeks between the first and second dose. (Strong NACI Recommendation)

For children 6 to 11 years of age (which is the age group in which the Moderna Spikevax 50 mcg primary series vaccine is authorized):

Moderna Spikevax (50 mcg dose) may be offered as an alternative to PfizerBioNTech Comirnaty (10 mcg dose), however the use of Pfizer-BioNTech Comirnaty (10 mcg dose) is preferred to Moderna Spikevax (50 mcg dose) to start or continue the primary vaccine series.

Recommendations on the use of Moderna Spikevax COVID-19 vaccine in children 6 to 11 years of Age Although risk of myocarditis/pericarditis with the Moderna Spikevax (50 mcg) in children 6 to 11 years of age is unknown, with a primary series in adolescents and young adults the rare risk of myocarditis / pericarditis with Moderna Spikevax (100 mcg) was higher than with Pfizer-BioNTech Comirnaty (30 mcg).

The first COVID-19 vaccine manufactured by a Canadian company will “very likely” not get the green light for emergency use by the World Health Organization (WHO) due to its ties to the tobacco industry.

The Quebec-based biopharmaceutical company Medicago’s vaccine marks the world’s first-ever plant-based jab for human use. The vaccine, called Covifenz, It’s also owned by tobacco company Philip Morris International — so the process is put on hold because it’s well known that the WHO and UN have a very strict policy regarding engagement with tobacco and arms industries. It’s very likely that it will not be accepted for emergency list using by WHO. Medicago’s COVID-19 vaccine is listed as “not accepted” in the WHO’s expression of interest phase.

Canada has a contract for 20 million doses and an option for up to 56 million more, but Canada does not need them. More than 85 per cent of Canadians over the age of five are now fully vaccinated and going forward Canada is relying almost solely on the mRNA vaccines from Pfizer-BioNTech and Moderna.
Canada had promised to donate any excess vaccines it purchased to COVAX. If the WHO rejects Medicago’s vaccine, Canada won’t be able to donate any of its doses to the Covax alliance, which is desperate for doses to reach its goal of vaccinating 70 per cent of people in every country by July.

Fully vaccinated travellers entering Canada will not have to show proof of a negative COVID-19 test as of April 1.

Passengers may still be subjected to random PCR testing at the airport though they will not be required to isolate while awaiting their results.

Unvaccinated Canadians and other travelers who are exempt from the vaccine mandate will still need to provide a negative rapid antigen or molecular test, or an accepted form of proof of recent infection to enter the country. Unvaccinated travelers will also be tested on arrival, again eight days later, and will be required to quarantine for 14 days.

All travelers will still have to use the ArriveCAN app or online form to enter their proof of vaccination and other required information within 72 hours before their arrival in Canada. Travelers who do not complete this submission may face testing and isolation requirements, regardless of vaccination status, according to the government.

The requirement to be fully vaccinated in order to board federally regulated air, rail, and marine transportation remains in effect. Cruise ship passengers will still need to provide a negative antigen test taken within 24 hours before the scheduled boarding time, but will no longer need to be tested again to get off the ship.

If you’re 12 or older, you’ll need to be fully vaccinated in order to board domestic flights, VIA Rail and Rocky Mountaineer trains, and cruise ships.

Health experts have warned since omicron took over as the dominant strain that everyone is likely to get COVID-19 at some point. Yet all of the data we have at this point suggests there are still millions of Canadians who haven’t been infected.

How can it be that two years into a pandemic marked by increasingly contagious variants, so many people remain COVID-free? What separates those of us who have tested positive from those who haven’t?

Reason 1: Because vaccines, masking and distancing works
Reason 2: Because you’ve remained totally isolated
Reason 3: Because you did actually have it, you just didn’t know
Reason 4: Because household transmission is not a given
Reason 5: Because, well, luck

While there are clear, well-established mitigation strategies that have helped lower individual risk of contracting COVID-19, a lot of it comes down to a hefty dose of just good luck. There’s a lot of randomness to COVID. There are people who seem to have minimal exposure who come down with it, and there are people who have heavy exposure who seem to do OK.

The truth is that experts are still learning about COVID-19.

https://theconversation.com/covid-pandemic-2nd-anniversary-3-things-we-got-wrong-and-3-things-to-watch-out-for-177618
Exactly two years ago, on March 11 2020, the World Health Organization (WHO) declared COVID-19 a global pandemic.

This was two months after there were reports of a mystery virus infecting people in Wuhan, the most populous city in central China. Early reports said the virus didn’t appear to be readily spread by humans. Well, the SARS-CoV-2 virus could indeed be spread by humans. It quickly travelled around the world, and has so far infected more than 450 million people. COVID-19, the disease it causes, has to date caused more than six million deaths, making it one of the most deadly pandemics in history. In those early days we knew very little about the virus and COVID.

Here are three things we realised were wrong as the pandemic wore on, and three things we need to keep a close eye on as we approach the endemic phase, where the virus continues to circulate in the population at relatively stable levels

1. Many were worried we wouldn’t get a vaccine
In early 2020 we didn’t know whether a vaccine against SARS-CoV-2 was possible. There had been previous attempts to develop vaccines against severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), two similar coronaviruses that also caused outbreaks this century. A few of these vaccines entered clinical trials, but none were approved.

Before COVID, the fastest developed vaccine was for mumps which took four years. But in under 12 months, Pfizer/BioNTech developed a successful vaccine. Now we have 12 vaccines approved for full use in different parts of the world, 19 for emergency use, and more than 100 still in the clinical trial stages. Both Pfizer and Moderna have also commenced clinical trials of an Omicron-specific vaccine. There are also several research groups around the world developing vaccines aiming to work against all SARS-CoV-2 variants.

2. Some thought we didn’t need face masks
In the early days, without a vaccine, to reduce transmission we had to rely on individual preventative measures such as hand hygiene, social distancing and face masks. Although there was widespread acceptance hand washing and social distancing protected against infection, face masks were much more controversial. Before April 2020, the US Centers for Disease Control and Prevention (CDC) advised against the wearing of face masks by the public. There were apparently two reasons for this. First, the CDC was afraid there wasn’t a sufficient supply of surgical and N95 masks, which were essential in high-risk settings. Second, it was thought at the time asymptomatic and pre-symptomatic people could not transmit the virus (we now know they can).Health authorities initially held off recommending face masks, but this quickly changed. However, on April 3 2020, the CDC changed its advice and recommended the general public wear multi-layered cloth face masks.

This has now been updated to wearing a well-fitting mask that is consistently worn. With the advent of Omicron, some experts say cloth face masks aren’t up to the task and people should at least wear surgical masks, or even better respirator masks like a P2, KN95 or N95.

3. We worried a lot about surface transmission
In the early days of the pandemic, it was thought contaminated surfaces were a major means of COVID transmission.

People wore gloves when going to the supermarket (some still do), and washed food packages once they got home. However, we now know the virus is spread primarily through aerosol and droplet transmission. When a person coughs or sneezes, droplets containing mucous, saliva, water and virus particles can land on other people or drop onto surfaces. Larger droplets tend not to travel very far and fall quickly. Smaller droplets called aerosols, can stay airborne for an extended period of time before settling. Scientists now believe transmission through touching contaminated surfaces is quite rare.

3 things to watch out for
There are three key issues we need to be aware of as COVID slowly becomes endemic.
1. Waning immunity
Many older and vulnerable people had their third dose in November or December last year, with their immunity now waning fast. We need to provide a fourth vaccine dose as soon as possible to the elderly and vulnerable.

2. New variants
There’s still the potential for new and more severe variants to hit us. One of the main reasons for this is the low rates of vaccination in many developing countries. The more the virus replicates in unvaccinated populations, the greater the chance of mutations and variants.

Vaccine manufacturers Pfizer and Moderna either manufacture the vaccine in their own facilities, or license the right to produce the vaccine in other countries. This puts it out of reach financially for most developing countries, who then have to rely on the COVAX initiative for supplies. COVAX is a worldwide facility funded by developed countries and donor organizations to purchase vaccines to be distributed to developing countries. Researchers at the Texas Children’s Hospital’s Center for Vaccine Development have unveiled a protein-based vaccine called Corbevax. It uses established and easy-to-manufacture technology, and is being provided patent-free to developing countries. It has now received emergency use authorization in India. It has over 80% efficacy against symptomatic disease, though this is against the no-longer dominant Delta variant. Trials are currently under way to determine its efficacy against Omicron. If approved, this should greatly help lift vaccination rates in many developing countries.

3. Long COVID
Politicians are ignoring long COVID. With thousands of cases a day, over the next year we will be getting a tsunami of people suffering from long-term health problems. So, we simply cannot ignore high case numbers and would be wise to retain at least some public health measures (for example, face mask mandates) in order to bring case numbers down.

The beginning of the end,

Governments are now dismantling public health measures such as the use of QR codes, social distancing measures and face mask mandates. Their thinking is that although case numbers are still quite high, hospitalizations are going down – and of course, elections are in sight. Chief public health officers, who used to give daily briefings, are now rarely seen. “Give us our freedom back” is now a commonly heard cry, even if the inevitable consequence means this is at the expense of elderly and vulnerable people.
In a nutshell, many believe we have moved already from epidemic to endemic status. As much as we all wish for this to be over and life to get back to normal, we aren’t quite there yet. But I think with better vaccines and improved treatments on the way, it’s at least the beginning of the end.

Pfizer-BioNTech COVID vaccine less effective against infection for kids 5 to 11, study suggests

The vaccine’s efficacy against infection among those children declined to 12 per cent at the end of January from 68 per cent in mid-December compared to kids who did not get vaccinated, according the study, which has not yet been peer reviewed.
Two doses of the Pfizer-BioNTech COVID-19 vaccine was protective against severe disease in children aged five to 11 during the recent Omicron variant surge, but quickly lost most of its ability to prevent infection in the age group, according to a study by New York State researchers.

“These results highlight the potential need to study alternative vaccine dosing for children and the continued importance layered protections, including mask wearing, to prevent infection and transmission,” the researchers said.

“It’s not surprising that protection against mild illness would wane, We know that Omicron is somewhat immune evasive for protection against mild illness. The goal of the vaccine is to protect against severe illness — to keep children out of the hospital.”