What Measures Can Prevent Pertussis Transmission?

Introduction

Pertussis, also known as whooping cough, is a highly contagious respiratory infection caused by a type of bacterium called Bordetella pertussis.¹ Outbreaks of pertussis date back to the 16th century, and it was considered a common childhood disease in the United States before the pertussis vaccine was introduced in the 1940s.²

Once inside the body, Bordetella pertussis sticks to tiny hair-like structures called cilia in the respiratory tract. It then produces toxins that affect the function of the cilia, causing inflammation and making it difficult for the individual to clear mucus from their lungs.² Bordetella pertussis can avoid the body's defence mechanisms and impair the ability of certain immune cells to move towards the site of infection.²

The symptoms of pertussis initially mimic those of a common cold, such as a sore throat and a runny nose, usually without a fever.³ However, after about a week, the individual may experience intense coughing episodes that are often exacerbated during nighttime. Breathing difficulties may cause coughing spells and cause a bluish hue in infants.³ Facial redness is another potential symptom, but this is more common in adults than in children. The persistent coughing can endure for weeks or even months.

Pertussis is often treated with the whooping cough vaccine.

Vaccination

As part of a wider initiative, individuals with pertussis (whooping cough) are administered a combination vaccine that also protects against other bacteria. It is recommended that children receive a combination vaccine called the diphtheria-tetanus-pertussis (DTaP) vaccine, a three-dose primary series vaccine that also protects them against diphtheria and tetanus.⁴ 

The acellular pertussis vaccine contains components of Bordetella pertussis that can stimulate an immune response in the individual, allowing their body to detect and destroy the bacteria before it can cause harm, whilst also ‘priming’ the immune system to respond quickly to the specific bacterium upon a second encounter.⁵

Healthcare providers recommend children receive five doses of the DTaP vaccine at various stages of their life:⁴

• First dose: 2 months old
• Second dose: 4 months old
• Third dose: 6 months old
• Fourth dose: between 15-18 months old
• Fifth dose: 4-6 years old

Adults are advised to receive a booster vaccine to prevent transmission.⁴ Pregnant people are also recommended to get vaccinated to protect infants that are too young to be vaccinated.¹

Booster shots are recommended for adults aged 19-64 years.⁴ These booster shots should be taken throughout life because immunity to pertussis will diminish over time.

The pertussis vaccine is effective, but it does not guarantee lifelong protection from the disease as the level of protection may gradually decrease over time - increasing the chances of reinfection and the disease spreading to unvaccinated individuals in the community.⁶ This is why it is important for as many people in a community as possible to get vaccinated.

Herd immunity

Herd immunity is a concept in epidemiology. Herd immunity states that when a significant portion of a population (or community) becomes immune to a disease, either through vaccination or previous infection, the spread of disease from person to person is markedly reduced.⁷

Other names for herd immunity are ‘community immunity’ or ‘herd protection’.

In the case of pertussis, if an individual with the disease is surrounded by people who are vaccinated against pertussis, the disease cannot easily spread from person to person, and the chances of someone becoming infected with the disease are significantly reduced.

Herd immunity aims to protect vulnerable individuals, such as infants who are too young to receive a vaccination and those with weakened immune systems (i.e. the immunocompromised). Herd immunity, however, does not confer protection against all vaccine-preventable diseases. A common example of this is tetanus.⁷ Nonetheless, it is crucial to maintain high vaccination coverage rates through immunisation initiatives to sustain herd immunity and prevent pertussis transmission within communities.

Personal hygiene measures

Pertussis is a highly contagious infection that spreads from person to person through respiratory droplets produced by coughing or sneezing.¹ The susceptible individual typically contracts the disease by breathing in the bacteria. Initial symptoms appear 7-10 days after infection and pneumonia is often a common complication of the disease.¹

Preventive measures include washing the hands with soap and water to prevent transmission.⁸ People should cover their mouth when they cough or sneeze, and immediately wash their hands afterwards. Tissues should be disposed of immediately. Any individual who is sick or showing symptoms of the disease is recommended to stay at home to prevent the spread of infectious respiratory diseases.⁴

Individuals with persistent coughing episodes that last longer than one week should wear a face mask to prevent transmission of the disease to others. Household members who are in close contact with an infected person should wear a face mask and stay more than 3 feet away from them.⁶

Isolation of infected individuals

People who are sick should be isolated and quarantined from others to limit transmission.⁸ Within their household, the infected individual should remain confined in their own quarters to reduce the chance of the disease spreading to other household members.

However, additional measures must be taken by other household members, such as receiving vaccination to limit the spread of the disease.

Post-exposure prophylaxis

Post-exposure prophylaxis (PEP) refers to preventive treatment that is administered after potential exposure to an infectious agent, such as bacteria, to prevent infection.⁹ The first-line treatment for pertussis is erythromycin, and alternative treatments are azithromycin and clarithromycin.¹⁰

The risk of pertussis transmission is high and it is therefore recommended for all household members to be treated with antibiotics.⁴

Public health interventions

While vaccination is crucial and remains the most effective way to prevent the transmission of pertussis, several other methods may limit the spread of the disease:

Contact tracing

One common method is known as contact tracing, which aids in the identification of individuals who may have been exposed to an affected individual. It can determine if a person should be recommended for PEP and what other measures should be taken to ensure the disease does not spread and affect others.⁹

Education campaigns

Education campaigns can also help to raise awareness by informing the public about the causes, symptoms and prevention of the disease, thereby increasing their willingness to receive vaccinations to prevent disease spread. These also encourage individuals to observe healthy practices such as hand hygiene and receiving medical care on time.

Education campaigns increase compliance by fostering community adherence to public health guidelines and recommendations, such as vaccination schedules. This also positively impacts herd immunity, making it more likely that a significant portion of a community gets vaccinated and reduces the spread of disease.

FAQs

Does a mask protect against pertussis?

Pertussis is highly contagious and wearing a face mask helps protect you from contracting it.

Does pertussis require airborne precautions?

It is recommended for people to wear a surgical mask within 3 feet of the infected person.⁶

What PPE is needed for pertussis?

Personal protective equipment (PPE) required for protection against pertussis includes eye protection, gloves (when providing direct contact with the infected patient), and a gown.

Summary

Pertussis is a highly contagious respiratory disease that is transmitted from person to person through droplets produced by coughs and sneezes. The incidence of the disease was extremely high in the early 20th century before the introduction of the pertussis vaccine in the 1940s. The disease is caused by the bacterium Bordetella pertussis, which releases toxins that make it difficult for the body to clear mucus from the lungs - causing symptoms like persistent coughing. 

Children are recommended to receive the full diphtheria-tetanus-pertussis (DTaP) vaccine series whilst growing up, and adults are advised to receive booster shots to confer immunity and prevent transmission to infants and vulnerable individuals. Like most vaccines, immunity may wane over time, and individuals may need subsequent vaccinations throughout life to ensure the disease does not spread and harm other members of the community.

Preventive measures include hand-washing with soap and water, wearing a face mask around infected individuals and those who are susceptible to the disease, and isolation of people with confirmed disease. Additionally, close contacts in a household should take antibiotics as recommended by their healthcare provider. Educational campaigns and contact tracing are additional preventive measures.