Why I Got COVID-19 After Vaccination | Bloomberg Opinion

Even after receiving both doses of the Pfizer-BioNTech vaccination, MARY Duenwald, a Bloomberg Opinion editor, tested positive for Covid-19. 

She speaks with Sam Fazeli, a Bloomberg Intelligence pharmaceutical sector expert, about her experience. The dialogue has been edited and condensed for your convenience. 

MD: I was just vaccinated against Covid - I received my second Pfizer shot a few weeks ago. I had hoped that meant I wouldn't get Covid, but this week I tested positive. Is that even possible? 

SF: Mary, thank you for sharing your storey with us. In truth, sterilising immunity, or protection that entirely prevents a virus from infecting you, is extremely unusual. Only one vaccination, the smallpox shot, has been demonstrated to provide that protection. If you recall, the phase III studies of the Pfizer-BioNTech and Moderna vaccines – likely the most effective so far – were 95% effective, which means that some vaccinated persons still had symptoms after the second dosage, albeit at a very low rate. Also, outside of a clinical trial, efficacy will be slightly lower; real-world research shows that efficacy is around 90%. It's also possible that you've been infected with a novel variation, such as B.1.526, which is currently circulating in New York.

MD: My symptoms are moderate, as if I'm suffering from a common cold. Is it safe to think the shot is still working to keep me safe? 

SF: Without a doubt. You'll never know how severe your symptoms would have been if you hadn't had the vaccine, but they may have been far worse. The vaccines are highly effective against serious and life-threatening diseases; in fact, their primary goal is to keep people out of hospitals and reduce their chances of dying. Even those that appear to be less effective against mild and moderate disease, such as Johnson & Johnson's injection, perform better against severe and critical illness.

MD: My symptoms are mild, as if I'm coming down with a cold. Is it safe to assume that the shot is still keeping me safe? 

SF: Without a question. You'll never know how bad your symptoms would have been if the vaccine hadn't been given, but they may have been far worse. The vaccinations are highly efficient against serious and life-threatening diseases; in fact, keeping patients out of hospitals and reducing their chances of dying is their major purpose. Even those that appear to be less efficient against mild and moderate disease, like Johnson & Johnson's vaccine, are more effective against severe and critical illness.

MD: I was tested the same day I learned I had been in contact with someone with Covid, and again the next day, and both tests came back negative. The positive test came a week later. Does that mean I wasn't infected by that person?

SF: No – there is an incubation period that can last as long as two weeks. It's possible that people who are vaccinated have a longer incubation period as the virus is hampered by the immune system. The other interesting question is whether you need to quarantine as long as an unvaccinated person with an infection does. Might you be safe sooner because you've had the vaccine? You might, but we just don't know yet.

MD: What should I learn from my experience about how safe a vaccinated person should feel and what precautions they should still take, especially in the presence of the unvaccinated? 

SF: People who have been vaccinated should feel safe unless the research shows otherwise. Currently, only a small percentage of those who have been vaccinated have developed severe infections, which is a good thing. At the same time, as long as there are people who have not been vaccinated, masking and distance should be continued - for their sake. 

MD: In a similar vein, some members of the Bloomberg Opinion team were concerned about the risks of an old person who had been vaccinated visiting unvaccinated relatives. Is that a risky proposition?

MD: After I get through this, will I be immune to future infections?

SF: It is possible that your infection has given you a second "booster," but I doubt anyone will ever be 100 per cent immune to mild infections. What would be interesting to know is whether you are infected with one of the virus variants. If so, we could then look at your immune response to see if it has changed and can give you better immunity to this new variant the next time you encounter it. 

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YES, YOU MAY CATCH COVID-19 AFTER VACCINATION. BUT DON'T WORRY...  Read on below to know more.

There's a new genre that didn't exist before the pandemic but is now unavoidable: let's call it the Covid Horror Story. 

These have spread like wildfire and feature pandemic scenarios that appear to be engineered to keep you scrolling and awake at night. OR A LIZARD GAVE ME COVID! or A MAN IN THE AREA CATCHES CORONAVIRUS THREE TIMES! Frequently, they aren't worth the fear. 

But now, one such case can be found on Bloomberg Opinion: Mary Duenwald, who used to edit our newsletter, acquired coronavirus more than two weeks after receiving both shots of the Pfizer-BioNTech vaccine, which is so good that some people are forgoing other vaccines in favour of it.

So, as Sam Fazeli explains to Mary and us, most vaccines don't truly prevent you from getting sick or dying from a disease; instead, they keep you from being severely sick or dying from it. 

Mary's case of Covid-19 is, indeed, fairly light. (I assume her immune system was boosted after a few months of editing this newsletter, but I don't have any evidence to back this up.) 

It's also possible that Mary got infected by one of the numerous varieties circulating, some of which appear to be more contagious than others. As a result, notes Lionel Laurent, the question of how to rapidly reopen economies becomes increasingly difficult. 

They also make it difficult for those who have been vaccinated to know how to act, as well as for organisations like the CDC to provide guidelines.

Many of us have imagined Covid vaccinations as magical elixirs that will just turn off the epidemic like a switch ever since modern science began producing them at breakneck speed. They don't operate that way, though. 

Even the ones that are considered to be less effective are nonetheless worth buying. The story of Mary should not keep you up at night or prevent you from being vaccinated. However, it should encourage you to continue to be cautious for a little longer.