The US manages 205.9 million doses of COVID-19 vaccines

The New York Times

Why vaccine safety numbers are still vague

When federal officials stopped administration of the Johnson & Johnson vaccine after six cases of a rare coagulation disorder, one fatal, of the 6.9 million people who received the vaccine, many critics noted that the risk of a serious condition so rare it was negligible – less frequent than from lightning strikes. But that percentage of about one in a million is far from certain. Doctors will eventually discover that the vaccine is not responsible for the condition. However, if the two are linked, it is also possible that the likelihood of an adverse effect is higher, even if it remains low. “Figures seem pretty solid, like, ‘Oh, it’s 10,'” said Caitlin Rivers, an assistant professor at Johns Hopkins University who studies infectious diseases. She said epidemiologists face similar uncertainties at the outset of disease outbreaks. “But they are estimates, and they will have to be fine-tuned, and they may have to be fine-tuned a lot, especially since the numbers are small.” Sign up for The Morning’s newsletter from the New York Times – How do we know how common this event is? If there is a link between the vaccine and this rare syndrome, new cases are likely to emerge now that the word is out. Regulators announced the break in part to alert doctors to the existence of this syndrome; when people start to search, they are more likely to find it and report it. With numbers so low, adding even a few more cases could increase the speed. (In recent days, Johnson & Johnson has reported two more possible cases, one in a woman and one in a man.) If there is a link between the vaccine and the syndrome, more people who have already received an injection may still be able to develop the condition. clotting problem as it appears to appear within a few weeks of vaccination. According to government estimates, about half of Americans who got the shot from Johnson & Johnson got it this month. One reason the Centers for Disease Control and Prevention vaccine safety committee wants to wait longer to update the guidelines on admission is to see what happens to this group. Since the first break was recommended, the number of Americans who have received the shot has risen to 7.7 million. Only some segments of the population may be at high risk for this problem, just as some populations are at greater risk for serious problems from certain diseases. Most cases so far have occurred in women between the ages of 18 and 50. Looking at six cases in that population, the syndrome appears to be slightly more common, although it is still very rare. If more cases are reported, it is also possible that this gender pattern will disappear. Dr. Tom Shimabukuro, a vaccine safety expert at the CDC who presented figures to the vaccine safety council this week, said all current calculations are still “crude.” – How can we tell that the clots wouldn’t have happened after all? It’s hard to say now. Studies of such events usually compare people who receive a drug or vaccine to a control group of people who have not. With a rare condition like this, that comparison couldn’t be easily made using clinical studies. Researchers are conducting a large-scale study of the health records of 12 million patients called the Vaccine Safety Datalink, comparing medical records of people previously vaccinated with those who receive an injection later – a system that does not rely on voluntary reporting. Those results will take a while. Researchers are also looking at what’s called a background figure of serious events – the likelihood that someone will develop a health problem, even if he or she has never received a vaccine. By comparing the number of events in humans receiving a vaccine with the percentage in the total population, an idea can be given as to whether the outcome of a particular patient is the result of the vaccine or rather a coincidence. Women under 50 – the group who may be at risk for the specific type of blood clot authorities have seen in the vaccinated patients – are more likely than the general population to get these blood clots just by living. – What’s a rate we should care about? Many medications given to sick people can have serious side effects for a fraction of those who use them. Physicians and patients routinely weigh such risks against the benefits of medical treatment. Birth control pills containing estrogen have often been discussed this week because they are a common drug with a risk of blood clots. Clots caused by birth control pills are different from the syndrome associated with the COVID vaccines, and some experts caution against comparing them directly. The type of clots caused by oral contraceptives usually form in patients’ legs, not their brains, but they can still be serious. The pills more than double a typical woman’s risk of such an event, meaning that between 3 and 9 out of 10,000 women who use the pills for a year will develop a clot. (Pregnancy, the condition in which birth control pills are often prescribed to prevent this, causes an even higher risk of blood clots.) “I will often say that the risk of developing a blood clot with birth control pills is comparable to having a very serious condition response to penicillin, “said Dr. Raegan McDonald-Mosley, an obstetrician-gynecologist and CEO of Power to Decide, a group dedicated to reducing unintended pregnancy. She regularly discusses and tells her patients the risk of blood clots. about the increase in risk and the overall magnitude of that risk. Most patients, she said, choose their form of contraception based on other considerations. However, the safety threshold for vaccines is generally higher than for other types of drugs. Like many Researchers have noted, COVID-19 also puts people at risk for serious blood clots – far more than any plausi estimate the vaccine effect. But not everyone who doesn’t get vaccinated will get sick. “The disease you get by chance, and the vaccine you prefer, makes it more difficult,” said Dr. Steven Black, professor emeritus of pediatrics at Cincinnati Children’s Hospital, who studies vaccine safety. For other vaccines, the risk of serious side effects is much lower than for birth control pills or penicillin – they generally affect less than 1 in 100,000 who receive a particular vaccine. That percentage is “clearly much, much lower than would be tolerated for a drug,” said Dr. Nicola Klein, director of the Kaiser Permanente Vaccine Study Center, who is involved in the Vaccine Safety Datalink study. Most other vaccines protect against diseases that are often rare. COVID-19, on the other hand, remains widespread in the United States and many parts of the world. Given the severity of the disease and its easy spread, the value of vaccination can now be higher than when such tradeoffs are usually considered. This article originally appeared in The New York Times. © 2021 The New York Times Company