Typhoid fever: What it is and how it's spread

Typhoid fever is an infection caused by Salmonella typhi bacteria. Typhoid fever-causing bacteria are closely related to other forms of salmonella bacteria that are more common in the U.S. Like other forms of salmonella, typhoid fever primarily spreads through contaminated food or water. The bacteria are shed in the feces of infected persons and through improper hygiene practices or poor sanitation infrastructure it is transmitted to other humans. This is known as the "oral-fecal route." Typhoid fever is a huge problem in densely inhabited areas that lack the modern infrastructure required for proper water sanitation. Symptoms of typhoid fever include fever, weakness, abdominal pain, and constipation or diarrhea. People can carry typhoid bacteria and spread it to others without being symptomatic themselves. For example, Mary Mallon, AKA "Typhoid Mary" was believed to have caused numerous typhoid outbreaks years apart in the early 1900s as a non-symptomatic carrier who worked in food preparation jobs.

Fortunately, there are typhoid vaccines

Typhoid can be prevented by a vaccine. The typhoid vaccine is typically administered as a series of injections, and it is recommended for people who are at increased risk of contracting the disease, such as travelers to certain parts of the world, people who work with typhoid bacteria in a laboratory, or people who are in close contact with someone who is infected with the bacteria. It is important to note that the vaccine does not provide 100% protection against typhoid and people who receive the vaccine should still take precautions to avoid exposure to the bacteria.

Two vaccines to choose from: oral vs injectable

There are two available typhoid vaccines:

1. Inactivated typhoid vaccine (Typhoid Vi Polysaccharide Vaccine, Typherix): This is an injectable vaccine given in the muscle, usually in the arm. It is given as a single dose, and a booster dose is recommended every 2-3 years for people who remain at risk of exposure to the disease.

2. Oral typhoid vaccine (Vivotif): This is a capsule that is taken orally. It is usually given in 3 doses, with the second dose taken one week after the first and the third dose taken 5 or more days after the second. This is a attenuated live typhoid vaccine.

Both vaccines are safe and effective at preventing typhoid, but the oral vaccine may be more convenient for some people. It's important to consult with a travel medicine specialist to determine which typhoid vaccine is best suited for you.

Who should get the typhoid vaccine?

The typhoid vaccine is recommended for people who are at an increased risk of contracting the disease, such as:

• Travelers to areas where typhoid is common (mostly developing countries) particularly if they will be staying with friends or relatives who live in those areas, or if they will be eating street food

• People who work in areas where typhoid fever is common

• Laboratory workers who may be exposed through work

• People who have close contact with someone who has typhoid fever

It's important to note that the vaccine is not 100% effective and people who are vaccinated may still get the disease, so it's important to still take precautions such as practicing good hygiene and sanitation when traveling to areas where typhoid is common.

Who shouldn't get the typhoid vaccine?

There are certain conditions that may make it unsafe to receive a typhoid vaccine. These include:

• Allergic reactions to any component of the vaccine, such as antibiotics or latex

• Pregnancy or breastfeeding

• A weakened immune system due to conditions such as HIV/AIDS, cancer/cancer treatment, or recent radiation or chemotherapy treatment

• Active infection or fever

It's important to let your healthcare provider know if you have any of these conditions or if you have had an allergic reaction to a previous dose of the vaccine.

Additionally, there are some specific contraindications for the live attenuated oral typhoid vaccine:

• People who have a history of a severe reaction to the oral polio vaccine (OPV)

• People who have a history of a severe reaction to the oral vaccine

• Children less than 6 years old

It's important to discuss with the healthcare provider if you have any contraindications before receiving the vaccine.

Where are typhoid outbreaks most common?

Typhoid is most common in Africa, India, Southeast Asia, Indonesia and other areas that border the Indian Ocean or South China Sea--particularly developing countries that lack modern sanitation infrastructure. Typhoid is less common in South America and Central America but it still may be recommended if you are traveling to areas with some risk of exposure.

What are the side effects of the typhoid vaccine?

Most people don't experience any side effects but the most common side effects of the typhoid vaccine are mild and include pain, redness, or swelling at the injection site, as well as fever, headache, and muscle aches. These side effects usually go away on their own within a few days.

Less common side effects include severe allergic reactions, which can occur in a small number of people. These reactions are rare and can include symptoms such as difficulty breathing, hives, and swelling of the face, lips, tongue, or throat. A very severe allergic reaction can cause brain swelling so it is very important to inform your doctor or healthcare provider right away if you experience any serious or unusual side effects after receiving the typhoid vaccine.

How long does typhoid vaccine immunity last?

The duration of immunity provided by the typhoid vaccine varies depending on the specific type of vaccine used.

• The inactivated (dead) typhoid vaccine, which is given as a single injection, provides immunity for up to 2 years. A booster dose is needed after 2 years to maintain immunity.

• The live attenuated oral vaccine (Ty21a) is taken as a capsule, and the immunity lasts for around 5 years.

It's important to note that both types of vaccines may not provide complete protection for everyone who receives it, and people who receive the vaccine should still take precautions to avoid exposure to the bacteria. If you are traveling to an area where typhoid is prevalent, or if you are at high risk for exposure to the bacteria, you should consult with a travel health specialist about whether you need to receive the vaccine or if a booster dose is needed.

Treating patients infected with typhoid fever

Typhoid fever is treated with antibiotics. The type of antibiotic used will depend on the susceptibility of the specific strain of Salmonella typhi that is causing the infection. Many strains of typhoid are very drug-resistant, so it's important to properly identify the typhoid strain before starting antibiotic treatment. It is important to complete the full course of antibiotics, even if symptoms improve before the medication is finished. If treatment is stopped too soon, the infection could return and could also lead to antibiotic resistance.

How to prevent typhoid fever

In the case of typhoid fever, vaccination is the most effective form of disease control. As previously mentioned, a typhoid vaccine is available and is recommended for people who are at increased risk of contracting the disease, such as travelers to certain parts of the world, people who work with typhoid bacteria in a laboratory, or people who are in close contact with someone who is infected with the bacteria.

Additionally, the following measures can help prevent the spread of typhoid fever:

• practice good hygiene, such as washing your hands frequently and thoroughly

• cook food thoroughly and eat it while it is still hot

• avoid potentially contaminated food or water

• avoid close contact with people who have typhoid fever

It's important to note that, even if you have been vaccinated or have had typhoid fever in the past, you can still become infected again. Therefore, it's important to continue to practice good hygiene and to avoid exposure to the bacteria.

Where can I get the typhoid vaccine?

The typhoid vaccine is available at any Away Clinic location.

Who makes the typhoid vaccine?

There are a few different manufacturers that make typhoid vaccines. The inactivated (dead) typhoid vaccine is made by companies such as Sanofi Pasteur, and the attenuated live vaccine (Ty21a) is made by companies such as PaxVax. The World Health Organization (WHO) also provides prequalified typhoid vaccines for use in low- and middle-income countries. These vaccines are manufactured by companies such as Bharat Biotech and the Serum Institute of India.

What are we doing to eradicate typhoid fever?

Efforts to eradicate typhoid fever are ongoing and involve a combination of strategies. Specifically, governments and non-profits involved are using vaccines, sanitation and hygiene interventions (including infrastructure), and public awareness campaigns to combat the disease.

One of the main strategies is the widespread use of vaccines to protect people from the disease. As mentioned earlier, vaccines are available and are recommended for people who are at increased risk of contracting the disease, such as travelers to certain parts of the world, people who work with typhoid bacteria in a laboratory, or people who are in close contact with someone who is infected with the bacteria. Research is also ongoing to develop new and improved typhoid fever vaccines, diagnostics and treatments. This can help improve the effectiveness of the current interventions and reduce the number of cases and deaths from the disease.

Another important strategy is improving access to clean water and sanitation. Typhoid fever is spread through contaminated water and food, so providing access to clean water and proper sanitation can significantly reduce the spread of the disease.

In addition, public health campaigns are being conducted to increase awareness of the disease, its symptoms and the measures that can be taken to prevent it. Health care providers are also trained to diagnose and treat the disease and to report cases to public health authorities.

WHO (the World Health Organization) is also working with other international organizations, governments and partners to control and eliminate typhoid fever by providing technical support, funding and advocacy.

It's important to note that while these efforts can greatly reduce the number of cases and deaths from typhoid fever, the disease is still a significant public health problem, especially in low- and middle-income countries where access to clean water and sanitation and health care are limited.

Drug resistant typhoid in Pakistan

Drug-resistant typhoid fever is a growing concern in Pakistan, as well as in other parts of the world. It occurs when the bacteria that cause typhoid fever, Salmonella typhi, become resistant to the antibiotics that are typically used to treat the disease.

In Pakistan, a strain of Salmonella typhi known as H58 has emerged, which is resistant to multiple antibiotics including fluoroquinolones, which have been the mainstay of treatment for typhoid for many years. This has made it more difficult to treat the disease and has led to an increase in the number of cases and deaths.

The spread of drug-resistant typhoid in Pakistan is thought to be related to a number of factors, including poor sanitation and limited access to clean water, which can lead to the spread of the bacteria. In addition, the overuse and misuse of antibiotics in both human medicine and agriculture can contribute to the development of drug-resistant bacteria.

To address this issue, Pakistan is using a combination of strategies including:

• Increasing access to clean water and sanitation

• Promoting the appropriate use of antibiotics

• Implementing widespread vaccination programs

• Conducting research to understand the epidemiology of drug-resistant typhoid and to develop new treatments and diagnostics

• Improving surveillance systems to track and respond to outbreaks of drug-resistant typhoid

It's important to note that this problem is not limited to Pakistan, drug-resistant typhoid is emerging in many other parts of the world, and it's becoming a global public health concern.