OPV: A Comprehensive Guide to Oral Polio Vaccine

Introduction

Oral polio vaccine (OPV) has been instrumental in the global effort to eradicate polio. It is a safe and effective vaccine that has saved countless lives. This article provides a comprehensive overview of OPV, including its history, development, and impact on public health.

History of OPV

The development of OPV began in the early 1960s. In 1961, Albert Sabin created the first effective OPV. This vaccine was later licensed in the United States in 1963 and became widely used throughout the world.

Development of OPV

OPV is a live attenuated vaccine, which means that it contains a weakened form of the poliovirus. When the vaccine is administered orally, the weakened virus replicates in the gut and stimulates the body's immune system to produce antibodies against all three types of poliovirus.

Impact of OPV on Public Health

OPV has had a profound impact on public health. Since its introduction, the incidence of polio has declined by over 99%. In 2018, only 33 cases of wild poliovirus were reported worldwide.

Benefits of OPV

OPV offers several benefits over other polio vaccines. These benefits include:

• Low cost: OPV is one of the most affordable vaccines available.
• Easy to administer: OPV can be administered orally, which makes it easy for healthcare workers to administer.
• Effective: OPV is highly effective in preventing polio.
• Long-lasting: OPV provides long-lasting immunity against polio.

Why OPV Matters

OPV is a critical weapon in the fight against polio. It is the only vaccine that can interrupt the transmission of the poliovirus from person to person. This is because OPV can shed virus in the stool, which can then be transmitted to others through contact with contaminated water or food.

How OPV Protects

OPV works by stimulating the body's immune system to produce antibodies against the poliovirus. These antibodies can then protect the body from infection by the virus. OPV is most effective when it is administered in multiple doses.

Types of OPV

There are two main types of OPV:

• Trivalent OPV (tOPV): This vaccine protects against all three types of poliovirus (types 1, 2, and 3).
• Bivalent OPV (bOPV): This vaccine protects against two types of poliovirus (types 1 and 3).

Dosage and Administration

OPV is typically administered in a series of four doses. The first three doses are given at 4, 6, and 12-18 months of age. The fourth dose is given at 4-6 years of age.

Side Effects of OPV

OPV is a safe vaccine, but it can cause side effects in some people. The most common side effects include:

• Fever
• Sore throat
• Muscle aches
• Fatigue
• Diarrhea

In very rare cases, OPV can cause serious side effects, such as:

• Vaccine-associated paralytic polio (VAPP): This is a paralytic illness that can be caused by the vaccine virus. VAPP is estimated to occur in less than one in 2.4 million doses of OPV.
• Intussusception: This is a serious bowel condition that can occur in infants. Intussusception is estimated to occur in one in 800,000 doses of OPV.

Contraindications to OPV

OPV is not recommended for people who:

• Have a severe allergy to any of the components of the vaccine.
• Are immunocompromised.
• Are pregnant.

OPV and the Global Polio Eradication Initiative

OPV has been a cornerstone of the Global Polio Eradication Initiative (GPEI). The GPEI is a global partnership of governments, health organizations, and other partners that was launched in 1988 with the goal of eradicating polio.

Since 1988, the GPEI has:

• Reduced the number of polio cases by over 99%.
• Eradicated polio from all but three countries (Afghanistan, Nigeria, and Pakistan).
• Prevented over 18 million cases of polio.

The GPEI is currently working to:

• Eradicate polio from the remaining three endemic countries.
• Maintain polio-free status in the rest of the world.

Transition from OPV to IPV

In an effort to eradicate polio and eliminate the risk of VAPP, the GPEI is transitioning from OPV to inactivated polio vaccine (IPV). IPV is a killed vaccine that does not contain live virus. This means that IPV cannot cause VAPP.

The transition to IPV is a complex process that requires careful planning and coordination. The GPEI is working with countries around the world to ensure a smooth and successful transition.

Conclusion

OPV is a safe and effective vaccine that has played a critical role in the fight against polio. The GPEI is working to eradicate polio from the world, and OPV is an essential tool in this effort.

Tables

Table 1: OPV Doses and Schedule

Table 2: Side Effects of OPV

Table 3: OPV and the GPEI

Stories and What We Learn

Story 1:

In 2018, a 2-year-old girl in Pakistan was paralyzed by VAPP. This was the first case of VAPP in Pakistan in over two years. The case was a reminder of the importance of OPV and the need to continue vaccinating children against polio.

What we learn:

• OPV is a safe and effective vaccine, but it can rarely cause VAPP.
• It is important to vaccinate children against polio to protect them from the disease and to prevent VAPP.

Story 2:

In 2019, a polio outbreak occurred in the Democratic Republic of the Congo (DRC). The outbreak was caused by a vaccine-derived poliovirus (VDPV), which is a strain of poliovirus that has mutated from OPV. The outbreak infected over 1,000 people and caused paralysis in over 200.

What we learn:

• VDPVs are a threat to polio eradication.
• It is important to maintain high vaccination coverage to prevent VDPVs from emerging.

Story 3:

In 2020, the GPEI paused the use of tOPV in all countries except for Afghanistan, Nigeria, and Pakistan. This pause was intended to reduce the risk of VDPVs and to accelerate the transition to IPV.

What we learn:

• The GPEI is committed to eradicating polio.
• The transition to IPV is a critical step in the eradication process.

Tips and Tricks

• Talk to your doctor about OPV and the benefits and risks of the vaccine.
• Make sure your child is vaccinated against polio according to the recommended schedule.
• If you are traveling to a country where polio is a risk, talk to your doctor about getting a booster dose of OPV.
• Wash your hands frequently with soap and water to prevent the spread of polio.
• Practice good hygiene to reduce your risk of infection.

FAQs

Q: Is OPV safe?
A: Yes, OPV is a safe vaccine. It has been used to vaccinate billions of children around the world.

Q: Can OPV cause polio?
A: Very rarely, OPV can cause VAPP. VAPP is a paralytic illness that can be caused by the vaccine virus.

Q: Who should not get OPV?
A: People who have a severe allergy to any of the components of the vaccine, who are immunocompromised, or who are pregnant should not get OPV.

Q: How many doses of OPV are recommended?
A: Four doses of OPV are recommended. The first three doses are given at 4