In 9th grade, my daughter wrote a history paper on the emergence of public health in Europe during the 14th century as a result of the plague. The bubonic plague pandemic lasted 9 years and killed about a third of the European population. I have no doubt I read the paper at the time and probably thought it was interesting that they figured out quarantine and isolation as tools to stop the plague. It never occurred to me that I would spend so much time thinking about the importance of quarantine and social distancing as we live through a pandemic 700 years later. Fortunately, science has advanced from believing mortality at the time was linked to the bad smells as they were unaware that rats spread the plague. However, the plague did lead to improvements in how animal waste was handled, changes to toilets and the handling of human waste.
The number of patients that came to the ER on a daily basis declined by about 50% last spring. Slowly, people started needing emergency services again, though our volume has been far from baseline. Our daily patient volumes were relatively similar from August through March though still way off baseline. If there’s any change over the last week or two it’s that as people start to get back to normalcy, we’re seeing an increased need for emergency care. While we’re still not back to pre-pandemic numbers, we are starting to feel busy. I’ve always loved taking care of the tourists that come to DC. Besides the patients from out-of-town I saw from the events on January 6th, I can’t remember the last tourist I saw. And while we’re not necessarily seeing the return of tourism to DC, I have started seeing patients from other states who are in town visiting family. People are definitely traveling again. That is also evidenced by the increase in beltway traffic and my increasing commuting time.
We continue to see Covid on a daily basis in the emergency department. As a clinician, we’re not noticing an increase or a decrease. It’s just steady. Our department continues to send 50-60 rapid Covid tests on patients each day. Our overall positive numbers are still in the same ballpark as they have been. Week to week it may go up or down a little bit but there has been no evidence of a surge or decline in Covid based on our test results. If there is a little bit of positive news this week, the percent positivity rate for both our symptomatic patient population and her overall patient population was lower this week than it was last week and also lower than her 6-week average. With the increases in ED patient volume, we are seeing more patients who require our “COVID isolation” status. However, the percentage of these patients who require admission has decreased the last couple of weeks. The total number of hospitalized COVID patients is also down a bit from last week, but still in the ballpark range it’s been living in for the last couple of months.
Blood clots have certainly been one of the complications we have seen from COVID consistently since the pandemic started. This week, the FDA pushed the pause button on the Johnson & Johnson vaccine that is being used in the US. There have been 6 recipients of the vaccine that developed a rare disorder involving blood clots within about 2 weeks after the vaccination. Nearly 7 million people have gotten the J&J vaccine in the US so far, so the possibility that a small number of people develop blood clots is not impossible. However, taken together with the small number of people that have developed very unusual blood clots after the AstraZeneca vaccine, the relationship cannot be ignored. There were two papers from the New England Journal of Medicine published about a week ago, that closely examined the patient population and the blood samples looking for laboratory abnormalities that may be associated with this relationship. The scientist were able to conclude that the AstraZeneca vaccine can result in a rare immunological response mediated by platelet activating antibodies that can lead to clotting and that younger people do appear more susceptible than older people. It appears that the patient’s platelet count lowers yet they are more likely to clump together. This condfition is starting to be referred to as “vaccine-induced immune thrombotic thrombocytopenia” or VITT. This is similar to something called heparin induced thrombocytopenia (HIT) that we see in the hospital for patients on heparin. Heparin is a strong blood thinner that is routinely used to treat and prevent blood clots. Yet heparin can also cause a reaction where antibodies bind to platelets and clots occur. It’s estimated that HIT occurs in about 0.76% of patients who are on IV heparin. Heparin is also the wrong treatment to give to someone with VITT, so part of the FDA pause on the J&J vaccine was to make sure the physician community was educated about this rare complication and better understood the treatment.
Medicine is about risk to benefit ratios. We need to put in perspective what a one in a million risk is. The CDC reports the odds of being struck by lightning in a given year are about 1 in 500,000. There are much higher risks of having a blood clot associated with smoking, taking birth control pills, COVID, etc (see image)….though those tend to be the traditional deep venous thrombosis or pulmonary emboli (still life threatening) but the J&J vaccine has been associated with a blood clot in the vein draining the brain. This central venous sinus thrombosis is very rare and very dangerous. Ultimately, the risk/benefit ratio of continuing to use J&J vaccine will come down to the math and what provides the most good to society–vaccination as a tool to end the pandemic or a 1 in a million chance of having a blood clot. What the scientists will also consider if whether there are subgroups of patients who are at higher risk and should use another vaccine. They will also consider what the prevalence rate of COVID is as risk adjustment changes in changes when considering a very low prevalence of COVID in the population compared to a high prevalence. The University of Cambridge has done the math to look at the risk of VITT based on prevalence of COVID (ratio of cases per thousands of people) and found that when COVID is moderately (6 cases/10,000 people) or highly prevalent (20 cases/10,000 people), using the Astra Zeneca vaccine is safer than the COVID risk. “The only scenario in which the risk-benefit balance currently leans away from the AstraZeneca/Oxford vaccine is for people younger than 30 years old, in low-risk covid-19 zones (<6 cases/10,000 people), according to the University of Cambridge analysis.” I also expect them to consider the role of aspirin and if a daily aspirin lowers the risk of blood clots. On the flip side, a daily aspirin could increase the number of patients with significant gastrointestinal bleeding much more frequently than 1 in a million and may not be ultimately seen as a benefit to society.
Some are asking why wasn’t this picked up in the trials. Vaccine trials were done on huge numbers of patients by medical standards—over 30,000 people. But it’s not until you get into real world situations and have millions of patients can you identify something that only happens with a one in a million frequency. I think this clearly shows that our post-vaccination monitoring process in working. Remember, in any group of people this large, there will be many blood clots. Statistically, if looking at 6 million people, some number of them would have a central venous sinus thrombosis in a two week period. One of the questions to the FDA and CDC scientists is whether these blood clots were caused by the vaccine or whether they occurred randomly after people got the vaccine.
Given the frequency of blood clots in the vaccine population, it will be interesting to see what happens with these two vaccines. The European Medicines Agency has stressed that the benefits of receiving the AstraZeneca vaccine outweigh the risks, while Britain has recommended that patients under 30 years old be given an alternative vaccine.
There are a couple of new studies out this week that suggest that the variant known as B.1.1.7 which was first identified in the UK, is more transmissible but does not appear to worsen severity. One study from the Lancet infectious Diseases, found that hospitalized patients with this variant had higher viral loads in patients who do not have this variant. In another study of the Lancet Public Health, researchers found no evidence of reported symptoms or disease duration associated with the B.1.1.7 variant. There is also no evidence that the frequency of reinfections was higher with this variant then with pre-existing variants. The studies are reassuring when it comes to understanding severity and reinfection rates but are concerning from a transmissibility perspective. As public health officials predicted earlier this year, the B.1.1.7 variant is now the most dominant coronavirus strain in the US and is leading to the rise in cases that we’re seeing, particularly in young adults who have not been vaccinated yet.
The vaccine is great but it’s not perfect. The CDC released data on 5800 “breakthrough” cases of COVID among the 66 million Americans who have been fully vaccinated. That’s a rate of 0.008%. Of these cases, there are 74 reported deaths and 396 hospitalizations. Also, about 29% have been asymptomatic. I spent about 10 minutes talking to a patient and his wife last night about the vaccine. They had heard that it makes you sick and were afraid of it. Certainly, a percentage of people feel crappy the next day. Yes, perhaps there’s a super small chance you still get COVID. But every doctor I know has been vaccinated. When the vaccine first came out in December, we had a priority list at the hospital and doc’s who weren’t on the priority list were ticked off. (ultimately, there was more than enough to go around and every clinical person had the chance to get vaccinated). For my friends who are doctors, everyone of their spouses has now been vaccinated as well as the overwhelming majority of their kids who hit the age threshold. The strategies of quarantine and isolation are great mitigation strategies, but let’s not forget they were developed in the Middle Ages. We need to take advantage of 21st century science to put this behind us.
Science matters. Wear a mask. Practice physical distancing.