A New Jersey family is questioning the efficacy of the Johnson & Johnson COVID-19 vaccine after three family members tested positive for the virus after taking the shot in March.

The father remains critically ill.

“I just can’t understand how he became so severe being fully vaccinated. I just don’t understand,” says Laura Eugene.

Eugene, her husband Francisco and their son all came down with the virus. They were vaccinated at the Javits Center in New York on March 6. Francisco, 59, is a diabetic. He is critically ill at JFK Hospital in Edison and is barely able to speak.

Eugene says that she is not sure how her husband was exposed to the virus.

“My husband doesn’t go out because I have COPD. We are very limited,” she says.

The Johnson & Johnson vaccine efficacy was reported at 72% in clinical trials. The Moderna and Pfizer vaccines are 95% effective.

Data from J&J confirmed a high efficacy when it comes to keeping people who get sick from being hospitalized. But doctors say that vaccines may not always work for everyone.

“There are some who may not generate enough antibodies to protect or generate immunity to COVID-19,” says Dr. Reynold Panettieri, of Rutgers University.

Panettieri says that it is not common to test for antibodies after vaccination to see if the patient is protected. It was also not clear if the Eugene family contracted a variant of the virus.

Panettieri says he's seen this before in some people who get the Pneumovax.

“People who get the pneumonia vaccine, there are some individuals who'll die of pneumonia because the immune system didn't generate the requisite immunity,” he says.

Eugene says that she has been sick for the last six days. She says that she cannot visit her husband in the hospital and that they can only speak on the phone or through FaceTime. She says that doctors have offered little explanation.

“They said we just have to wait every day to see how he responds. It’s up to him now, how his body responds,” Eugene says.

Health experts say that this is why it is important for everyone to continue wearing masks and practice good hygiene after vaccination.