Contraindications and Precautions to Vaccination
The rVSV-ZEBOV vaccine should not be given to people with any of the following.
- Known severe allergy, such as anaphylaxis, to any component of the vaccine, including rice protein
- Clinical evidence of a systemic infection or other acute intercurrent illness at the scheduled time of vaccination† (e.g., oral temperature >38°C [100.4°F], systemic symptoms)
- Presence of any clinically significant medical condition, past medical history, pre-existing illness (e.g., acute malignancy, history of Guillain-Barré syndrome, history of neurologic disorder that may increase risk, active autoimmune disorder or immunosuppression) that in the opinion of the healthcare provider may place the individual at an unreasonably increased risk of a serious adverse event following vaccination
- Unwillingness to complete the informed consent process and sign the consent form
†Vaccination may be rescheduled at a later date if the conditions resulting in ineligibility are no longer present.
While pregnancy and lactation are not absolute exclusion criteria for receiving rVSV-ZEBOV, live attenuated vaccines are generally contraindicated during pregnancy. Women of reproductive age should be counseled on the potential fetal risk(s) of vaccination. Determination of whether to receive rVSV-ZEBOV should be made on an individual basis, in consultation with a healthcare provider, based on the benefit/risk of vaccination against the risk of exposure to Ebola virus.
Laboratory and healthcare workers at risk for occupational exposure to EBOV who receive IND-labeled vaccine must continue to adhere to recommended biosafety guidelines and infection prevention and control procedures. People responding to an EVD outbreak must wear recommended personal protective equipment and follow proper procedures to prevent infection upon direct contact with a suspected or confirmed Ebola patient or contact with the patient’s body fluids, even if the responder received the IND-labeled vaccine.
Among the 15,399 adult subjects vaccinated with rVSV-ZEBOV during the clinical development of the vaccine, there were two reports of serious vaccine-related pyrexia and two reports of non-fatal anaphylaxis. Following vaccination with rVSV-ZEBOV, administering healthcare providers should monitor vaccinated individuals for signs and symptoms of hypersensitivity reactions. Appropriate medical treatment and supervision must be available in case of an anaphylactic event following the vaccine administration. Each vaccinated individual should be observed for a minimum of 30 minutes post-vaccination.
Vaccination with rVSV-ZEBOV may not protect all individuals. The safety and effectiveness of rVSV-ZEBOV have not been assessed in immunocompromised individuals. The vaccine may be less effective in immunocompromised individuals. To date, a small number of HIV-positive adult subjects have been vaccinated with rVSV-ZEBOV in the Partnership for Research on Ebola Virus in Liberia’s (PREVAIL) first study (PREVAIL I). Additional studies are ongoing to evaluate the use of rVSV-ZEBOV in HIV-positive individuals who are not severely immune compromised. The risk of vaccination with rVSV-ZEBOV, a live virus vaccine, in immunocompromised individuals should be weighed against the risk of EBOV disease.
Because rVSV-ZEBOV is produced with rice-derived recombinant human serum albumin, precautions should be taken with individuals allergic to rice. Individuals with a history of severe allergic reaction such as anaphylaxis to rice protein should not receive rVSV-ZEBOV.
Attenuated VSV vaccine virus RNA has been detected by reverse-transcription polymerase chain reaction (RT-PCR) in urine up to seven days post-vaccination, in blood and saliva up to 14 days post-vaccination, and in fluid from skin vesicles up to 20 days post-vaccination. Transmission of vaccine virus through close personal contact is theoretically possible. Healthcare providers administering vaccine should exercise appropriate infection control practices. Vaccine recipients should avoid
- Sharing needles, razors, toothbrushes, eating utensils, drinking from the same cup, and open-mouth kissing for two weeks after vaccination; if oral sores develop after receiving vaccine, vaccine recipients should avoid these activities until the sores heal.
- Close contact and association with immunocompromised individuals, pregnant or breastfeeding women, and children less than 1 year of age for up to six weeks following vaccination.
- Exposing livestock to the recipient’s blood and bodily fluids for up to six weeks following vaccination.
Considerations for special populations
There are no well-controlled studies of rVSV-ZEBOV in pregnant women. Data available from human clinical trials with rVSV-ZEBOV are not sufficient to establish whether the vaccine poses a risk during pregnancy. In a randomized, unblinded vaccine study in Sierra Leone, there were no statistical differences in pregnancy loss among those who were vaccinated versus those unvaccinated. Likewise, there were no external congenital abnormalities among babies born to women who were part of the vaccine study.
The World Health Organization recommends the use of rVSV-ZEBOV in pregnant and breastfeeding women in areas experiencing an active EBOV outbreak, in the context of rigorous research or through a compassionate use protocol. The risk of exposure to EBOV should be weighed against potential vaccine-related risk during pregnancy based on individual informed decisions.
Data are not available to assess the impact of rVSV-ZEBOV on women’s breast milk, its effects on the breastfed child or on women’s milk production. The child’s development and health benefits of breastfeeding should be considered along with the mother’s clinical need for rVSV-ZEBOV and any potential adverse effects on the breastfed child from rVSV-ZEBOV or from the mother’s risk from or susceptibility to Ebola virus.
A total of 542 older adults received rVSV-ZEBOV during clinical trials of the vaccine. Although this was inadequate to determine whether the immune response in older adults (≥ 65 years) is different from younger participants, the FDA-approval of rVSV-ZEBOV for prevention of disease caused by EBOV in adults (≥ 18 years) is inclusive of older adults without an upper age limit.
Vaccine adverse events
The most commonly reported injection site adverse events among the adults vaccinated with rVSV-ZEBOV during clinical trials were injection site pain (70%), swelling (17%), and redness (12%). The most commonly reported systemic adverse events following vaccination with rVSV-ZEBOV were headache (37%), feverishness (34%), muscle pain (33%), fatigue (19%), joint pain (18%), nausea (8%), arthritis (5%), rash (4%) and abnormal sweating (3%). The potential for previously not known, rare, serious events following vaccination may be possible. Administering healthcare providers should monitor individuals for signs and symptoms of reactions following vaccination. Appropriate medical treatment and supervision must be available in case of an anaphylactic event.
Some vaccinated individuals may experience arthralgia and arthritis after vaccination. In general, arthritis began one week after vaccination and resolved within a week after onset. However, some vaccinated individuals reported prolonged and recurrent arthritis symptoms. One post hoc analysis identified women and individuals with a medical history of arthritis to have a 2.2-2.8 times higher risk of developing post-vaccination arthritis.
Overall, reported vaccine-related severe adverse events (SAEs) were rare. Across 12 studies, out of 19,184 people who received the vaccine, three SAEs were judged to be related or possibly related to the vaccine: one febrile reaction, one anaphylaxis, and one influenza-like illness. All three of these SAEs resolved without sequelae. An additional case of anaphylaxis was identified in data provided to FDA and resolved without sequelae.
Limitations of vaccine effectiveness
The onset of protection and the duration of protection against EBOV following vaccination with the rVSV-ZEBOV is unknown. In addition, vaccination with the rVSV-ZEBOV may not protect all individuals. Vaccinated individuals should continue to adhere to recommended infection control practices to prevent EBOV infection and transmission.