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When I was vaccinated against Covid-19, I felt a deep sense of relief: no more worries about personally catching the disease.

So when I noticed mild, Covid-19-like symptoms two months later — stuffy nose, chest congestion, and an upset stomach — I thought they were due to seasonal allergies. I was shocked a few days later when a test for Covid-19 done in preparation for an unrelated medical procedure came back positive.

Not believing the result, I got tested again. And again. Over a five-day period I had four PCR tests — two were positive, two were inconclusive — and a false negative rapid antigen test.


I quickly went about quarantining and notifying recent contacts. I soon began receiving multiple calls from my city’s Board of Health, whose representative told me she knew of several other people who had also tested positive even though they were fully vaccinated.

My experience shows that testing for Covid-19 isn’t perfect. Rapid antigen tests detect proteins that are part of SARS-CoV-2, the virus that causes Covid-19. They have a fast turnaround time, but aren’t as accurate as the gold-standard PCR test. In people with Covid-19 symptoms, rapid tests correctly detect the virus only 80% of the time. In those without symptoms, it drops to 40%.


PCR tests, in contrast, tend to have much higher sensitivities, above 95% across the board.

How samples are collected can also affect the results of Covid-19 testing. I know this happens because I have had many Covid-19 tests over the past year. At some test centers, the clinician inserted the swab into the very back of my nose, known as the nasopharyngeal space. Some say it feels like the swab is heading into the brain. In other tests centers, the clinician barely scraped the lower rim of my nose; that’s called a nasal swab. Those made me wonder if it collected any sample at all. I’ve since learned that nasal swabs can miss detecting the virus in those with low viral loads.

While vaccination confers essentially 100% protection from Covid-19-related hospitalization and death, it doesn’t entirely prevent people from catching the infection in the first place.

A recent study from the University of California, San Francisco, tracking more than 30,000 health care workers showed an infection rate after vaccination of approximately 1%, meaning that infection is rare but still a threat. The Minnesota Department of Health announced it was investigating several of these “breakthrough” cases, as has the Oregon Health Authority. In mid-April, the Centers for Disease Control and Prevention reported 5,800 breakthrough infections to date among the millions of Americans who have been fully vaccinated.

Reports of 95% efficacy rates in vaccine clinical trials do not necessarily translate to real-world effectiveness of that magnitude, and can create a false sense of reassurance when it comes to asymptomatic or mild infections. The Pfizer trials only tested volunteers for SARS-CoV-2 if they developed symptoms after getting the vaccine or the placebo, leaving out those who may have been asymptomatically infected. Moderna trials also primarily looked at preventing symptomatic disease.

The lower efficacy rates in the clinical trials of the J&J vaccine may be more real-world, as they included asymptomatic PCR testing of participants, had more diverse patient populations, and were done later in the pandemic, when more viral variants had been identified. These differences may account for the lower efficacy rate of this vaccine — 74% for preventing asymptomatic infections — compared to 80% for Pfizer and Moderna’s vaccines, according to a recent Mayo Clinic study.

Here’s what I think all this means.

No vaccine is 100% effective at preventing Covid-19. The ones we have, though, are very effective at preventing severe illness, death, and reducing viral load in people unlucky enough to contract post-vaccination breakthrough infections. The focus now must remain on getting as many people vaccinated — and tested — as quickly as possible, so we can bring the pandemic to an end as soon as possible. To do this, we need more streamlined access to vaccinations and testing.

Regardless of vaccination status or prior infection, anyone with signs or symptoms of Covid-19 should get tested, as well as anyone who has been in close contact (within 6 feet for 15 minutes or more) with somebody with confirmed Covid-19. According to the CDC, people who have been fully vaccinated and have no symptoms following an exposure do not need to be tested.

In Massachusetts, where I live and work, the Stop the Spread initiative and organizations such as Transformative Healthcare are making free Covid-19 testing more widely available.

On the federal level, the Biden administration has already issued multiple executive orders to tackle the virus and expand Covid-19 testing for children and underserved populations, including a $650 million investment for K-8 schools and homeless shelters.

Even with nearly 25% of the U.S. population fully vaccinated, I — and others like me — are proof that now is not the time to let our guards down. Vaccines are necessary, but not sufficient for addressing Covid-19. Get vaccinated, but do not throw caution to the wind with regard to mask-wearing, basic hygiene, and physical distancing. It won’t be until we establish herd immunity that we can achieve our goal of eradicating this virus.

Stephen M. Tourjee is a child and adolescent psychiatrist; founder of Northshore Minds, a mental health practice north of Boston; associate director of Massachusetts General Hospital’s Transitional-Age-Youth Program; and an instructor in psychiatry at Harvard Medical School.

  • Yea that’s good and all but what happens when we run out true this virus never going away lol but they are still high chances at stake and they will always be besides people who don’t give a bleep these are people lives sorry if some of you had any brains people wouldn’t be dying that’s all I got to say about that

  • What this all means is that this pandemic is going to go on for many years. Everything we are doing now, from masks to distancing to lockdowns, will be the norm for years to come. With this virus constantly mutating into deadlier forms there is no way it can be eradicated. Sorry to be a debby downer. But the sooner everyone starts to accept the new world and adjust accordingly, the better off we will all be.

  • Me and my wife were both treated to the same outcome. Currently we are doing much better and are confident we will be fine in due time. Glad to have had the shot first because I think the outcome could have been more severe without.

  • I received my second dose on March 31 last Tuesday my husband who has not been vaccinated at all said he wasn’t feeling good and had a cold I told him to go get tested he refused two days after I came down with the same symptoms stuffy nose little tired and loss of taste oh, he also had a low-grade but I did not. I went today to get a Covid test and I am waiting the results but I’m pretty sure that I have the virus my husband goes out all the time and I purposely got the vaccine to protect myself but I think I was probably already infected by him before the second vaccine built up immunity towards it.I probably won’t know for a day or two from the pharmacy but if you’d like to contact me via email feel free

  • We know that it can happen. But you don’t say what your case was like when it DID happen. Experts say vaccination is likely to reduce the severity of infection, should there be a “breakthrough case.” Did that happen to you ? In other words, how severe was your case?

  • The chance of being killed in a car crash is 1%, the chance of catching covid after vaccination is .007% and dying from covid after vaccination even less. Are we going to tell people not to drive anymore? stop with the scare tactics, once your vaccinated your are safe and safe to others.

    U.S. health officials have confirmed fewer than 6,000 cases of Covid-19 in fully vaccinated Americans, CDC Director Rochelle Walensky said.
    That represents just 0.007% of the 84 million Americans with full protection against the virus.

    • Practicing social distancing and wearing face masks are not scare tactics. It is common sense. Even though some are vaccinated and the data is looking good, there is still a lot we don’t know. There are also unvaccinated children that are vulnerable right now. Why not work together to protect them and others that are not vaccinated yet so that everyone in our society can finally be safe.

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