Pertussis is a highly contagious respiratory infection spread by droplets when an infected person coughs or sneezes, or via direct contact with respiratory secretions of the infected. The disease affects people of all ages, and infant who are too young to be vaccinated are most vulnerable. Young children and particularly infants have a much higher risk of severe complications from the infection and the disease may be fatal.
In recent years, resurgence of pertussis has been observed in countries with high vaccination coverage, such as Australia, Japan, United States and Europe. Regionally, there is also a significant increase in the number of reported pertussis in Mainland including Guangdong Province. In Hong Kong, there has been a surge in the notified pertussis cases since 2017 and the increasing trend continued through 2018. There are 110 cases in 2018 and 38% of these affected infants are less than 6 months old.
Pertussis is most dangerous in infants. In infants younger than 2 months of age infected with pertussis, 90% will require hospitalization, 76% will die of pertussis-related complications. In infants young than 1 year old who are hospitalized because of pertussis, 1/100 will die of the disease.
The Scientific Committee on Vaccine Preventable Disease (SCVPD) under the Centre for Health Protection of the Department of Health recommends that pregnant women receive one dose of acellular pertussis-containing vaccine during each pregnancy as part of routine antenatal care regardless of previous vaccination and natural infection history against pertussis, as a measure to provide direct protection for infants against the disease.
The SCVPD recommends that the vaccination can be conducted at any time in the second or third trimesters, preferably before 35 weeks of gestation for transplacental transfer of maternal vaccine-induced antibodies to the baby. It takes two weeks for antibodies to develop after the vaccination and the World Health Organization (WHO) recommends that the vaccine be given preferably at least 15 days before the end of pregnancy. If women have not received any pertussis-containing vaccine during pregnancy, they would still benefit by receiving one dose of vaccine as early as possible after delivery, preferably before discharge from the hospital for indirect protection to infants.
Based on the safety data from a prospective observation study, pertussis vaccination has shown no vaccine related adverse effect on pregnancy or on the health of fetus/newborn child.
If you are about to take Pertussis vaccine, please check if you have any of the following conditions. If so, you are not suitable to get vaccinated:
Known hypersensitivity to any component of the vaccine;
History of hypersensitivity or severe adverse reactions after previous pertussis vaccination.
Very common and common reactions after Pertussis (1/10 to 1/100):
Rash, injection site reactions (pain, redness and swelling of the injection site or less commonly swelling of the entire arm where the shot was given);
Fever > 37.5℃ (including fever > 39℃)
Rash, swollen glands;
Nausea, diarrhoea, vomiting, stomachache;
Chills, sore joints;
Rare reactions (1/1000 – 1/10000) and very rare reaction (<1/10000) have also been reported. These include fainting, severe shoulder pain and have difficulty in moving the arm where the shot was given, a severe allergic reaction such as difficulty in breathing, restriction of the airways, convulsions.