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Whooping Cough Booster Vaccines Wear Off

While whooping cough vaccine protects infants and young children, booster doses wear off quickly according to scientists from the Queensland Children’s Medical Research Institute.

However, while three doses of the vaccine in the first 6 months of life provides good protection for children up to 4 years old, A/Prof Stephen Lambert says that boosters given after this time wear off quickly. “A key message from this study is that with a good but still not perfect vaccine, reaching high coverage becomes even more important from a population health perspective,” he said. “Parents can be reassured that the vaccination still offers the best protection against developing whooping cough, as children who aren’t vaccinated have a much greater risk of contracting the disease and developing serious complications.

The study, which was published in the Medical Journal of Australia, followed the switch in 1999 from a whole cell vaccine to an acellular vaccine in Australia’s national immunisation schedule, as the latter had fewer side-effects.

Whole cell vaccines contain whole pertussis organisms that have been chemically inactivated. Acellular vaccines contain a small number of key proteins from the whooping cough organism and have a much lower risk of adverse events.

A 2012 QCMRI study found that the nation-wide outbreak of whooping cough (pertussis) that started in 2009 was partly due to the reduced effectiveness of the acellular vaccine. However, Lambert said the latest study confirmed the benefits of the acellular vaccine.

“We know from these Queensland data that the current acellular vaccine for young children remains highly effective,” he said. “Other research has shown that children unlucky enough to get whooping cough after being vaccinated will have a milder illness for a shorter time than those who have not received the vaccine.

“But these findings could go some way to explaining why we saw a resurgence of pertussis in Australia, particularly in older children. In making the switch in vaccines in 1999 we may have traded off some of the protection whole cell vaccines provided in exchange for a better-tolerated vaccine.

“Looking at the bigger picture, it shows us that we don’t yet have the perfect whooping cough vaccine, and it gives us cause to work towards developing a more effective as well as a safe vaccine for whooping cough.”