After the J&J vaccine pause, many people understandably have questions about the safety of the one-dose Johnson & Johnson COVID-19 vaccine. The J&J vaccine pause went into effect April 13, 2021 and it’s unclear how long it will remain unauthorized for public use. Another round of clinical trials to make sure it’s safe is underway. It’s expected the J&J vaccine will be available again in a few weeks or months.

Public trust has eroded in this immunization following the J&J vaccine pause. Many people have already gotten it and are worried about potential adverse effects, and the pause has people who were going to get it questioning if it’s a good idea to get immunized. Here is our guide to the most common questions about the J&J vaccine pause and what to do if you’re concerned:

Why Was the J&J Vaccine Paused?

The J&J vaccine was paused because of a link between six or seven people who experienced a rare form of blood clots following its administration. These blood clots led to cardiovascular events including stroke in a few people. These people were all women between the ages of 18-48 and all of them started to experience these symptoms 6-13 days after receiving the vaccine. At least one woman passed away as a result of a stroke.

The form of blood clots potentially caused by the J&J vaccine is not very common and is not treated with standard blood thinner drugs like heparin. Blood clots following the vaccine are considered extremely unlikely, since only about seven people out of the seven million people who were administered the J&J vaccine have experienced these effects thus far.

Do these potential risks affect the other COVID-19 vaccines available?

At this time it is not believed there are any cardiovascular or other risks associated with the Pfizer or Moderna vaccines. These potential blood clot issues seem limited to the J&J vaccine—and similar AstraZeneca vaccine in other countries—in particular, so if you have received or are going to receive one of the other COVID-19 vaccines, it’s recommended you proceed as normal.

If I already got the J&J vaccine, what do I do now?

If you are one of the millions of people who already received the J&J vaccine, the good news is it’s highly unlikely anything adverse will happen to your health. The odds of a cardiovascular event following this vaccine appear to be literally one in a million, at most. 

However, looking out for signs of a potential cardiovascular event and alerting your health provider to the fact that you received this vaccine may help give you some peace of mind.

If you received the vaccine a month or more ago, you are considered past the possibility of an adverse reaction. All the reactions that have occurred took place between 6-13 days after administration of the vaccine, with most taking place around nine days after receiving it.

What are the possible signs I should look out for? 

The signs of an adverse reaction you should be concerned about from the J&J vaccine are not the standard side effects such as muscle aches, fever and chill that resolve themselves within a few days after receiving the shot.

Instead, be on the lookout for a very intense headache that lasts more than a few days, intense pain in your legs or arms, abdominal pain, or shortness of breath. If you experience this between one and three weeks after administration of your J&J vaccine, contact your health provider.

Be aware that this type of blood clot should not be treated with heparin—a blood thinner that is typically prescribed for blood clots—so if you are experiencing any of these symptoms it’s very important to tell your health provider when you received the J&J vaccine.

If I was going to get the J&J vaccine, what do I do now?

The J&J vaccine pause means if you were going to receive the vaccine in the near future, you are now no longer going to. If you had an appointment you don’t have to go in, and you should make an appointment to get another type of COVID-19 vaccine if you want one.

It is still recommended that everyone who can do so get vaccinated against COVID-19, since the risks of getting sick from COVID-19 far outweigh the risks associated with any of the vaccines. The FDA and CDC have stressed that the J&J vaccine pause is due to an “abundance of caution” and that while more studies are needed to determine the real risk, it is likely lower than the risk of complications from COVID-19.