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.