ProQuad is a combination vaccine designed to protect against four viral infections: measles, mumps, rubella, and varicella (chickenpox). It is a live attenuated vaccine that contains weakened forms of these viruses, which trigger the immune system to develop immunity without causing the diseases themselves. ProQuad is administered as a single-dose injection and is typically recommended for children and adults who have not been previously vaccinated or who require a booster. It provides a convenient way to prevent these four infectious diseases with a single vaccine.

Pharmaceutical Properties:

• Formulation: ProQuad is available as a lyophilized (freeze-dried) powder that is reconstituted with the accompanying diluent before administration.

• Components:

  • Measles virus (live, attenuated)

  • Mumps virus (live, attenuated)

  • Rubella virus (live, attenuated)

  • Varicella virus (live, attenuated)

• Adjuvants: The vaccine does not contain any adjuvants as the live attenuated viruses themselves are sufficient to stimulate an immune response.

• Stability: ProQuad is stable when stored in a freezer (between -15°C and -50°C) before reconstitution. After reconstitution, the vaccine should be used within 30 minutes and cannot be stored.

Indications for Use:

• Primary Prevention of Measles, Mumps, Rubella, and Varicella: ProQuad is indicated for the active immunization of individuals who are at least 12 months of age and older, to prevent measles, mumps, rubella, and varicella.

• Booster Doses: It can also be used as a booster for individuals who have previously received the single-dose vaccines for one or more of these diseases, depending on vaccination history and medical advice.

• High-risk Populations: In some cases, ProQuad may be recommended for high-risk individuals, including those who are likely to be exposed to these viruses or those who are planning travel to areas where these diseases are endemic.

Mechanism of Action:

ProQuad works by introducing weakened forms of the four viruses into the body. These weakened viruses are not capable of causing disease, but they stimulate the immune system to produce antibodies and memory cells that recognize and fight off the viruses if the person is later exposed to them.

• Measles: The live attenuated measles virus in the vaccine causes the body to produce immunity against the virus.

• Mumps: Similarly, the mumps virus component stimulates the body to generate immunity against mumps infection.

• Rubella: The rubella virus in the vaccine triggers the immune system to produce antibodies that protect against rubella.

• Varicella: The varicella virus stimulates immunity against chickenpox.

Once vaccinated, the immune system can quickly respond to any subsequent exposures to these viruses, providing lifelong protection in most cases.

Clinical Protocol in Dubai:

The vaccination schedule for ProQuad in Dubai follows the standard immunization guidelines outlined by the Dubai Health Authority (DHA).

1. Administration Schedule:

   • First Dose: ProQuad is typically administered as a first dose to children at 12–15 months of age.

   • Second Dose: The second dose is usually given between 4–6 years of age. This second dose ensures maximum protection and reduces the risk of breakthrough infections.

   • Catch-Up Vaccination: In some cases, unvaccinated individuals who missed the routine vaccinations can be given ProQuad according to their age and medical history.

2. Post-Vaccination Monitoring: After vaccination, the individual should be observed for 15 minutes for any signs of allergic reactions. Common side effects include fever, mild rash, and soreness at the injection site.

3. Contraindications and Precautions: ProQuad should not be administered to individuals who have a history of severe allergic reactions to any of its components. People with weakened immune systems (e.g., those undergoing chemotherapy or with HIV/AIDS) should consult their healthcare provider before receiving the vaccine.

4. Special Considerations: Pregnant women and individuals planning pregnancy should avoid ProQuad, as the live vaccines may pose a risk to the fetus.

Other Characteristics:

• Storage: ProQuad must be stored in a freezer (between -15°C and -50°C) before reconstitution. After mixing with the diluent, the vaccine must be used immediately and cannot be stored.

• Shelf Life: The shelf life of ProQuad in its unconstituted form is 24 months, while the reconstituted vaccine must be used within 30 minutes.

• Contraindications: ProQuad is contraindicated in individuals with known hypersensitivity to any component of the vaccine. It is also not recommended for individuals with active, untreated tuberculosis or any other severe conditions that affect the immune system.

Conclusion:

ProQuad is a highly effective combination vaccine that protects against four dangerous viral infections: measles, mumps, rubella, and varicella. It is an essential tool in preventing these diseases, which can have severe consequences, particularly in young children and adults. By offering protection against these infections in one convenient vaccine, ProQuad simplifies the vaccination process and enhances compliance with immunization schedules. In Dubai, the vaccine follows well-established guidelines and offers significant protection to the population, especially as part of routine childhood vaccinations.