Home Immunity MenACWY adolescent meningitis vaccination program boosts herd immunity at all ages

MenACWY adolescent meningitis vaccination program boosts herd immunity at all ages

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Researchers at the University of Oxford today reported the results of a large-scale study that looked at the impact of the UK’s MenACWY vaccination program on the carriage of meningitis bacteria in the throat British teenagers. They demonstrated the impact of the vaccine by generating herd protection, also called herd immunity, which protects all age groups

In the study, which is published in Clinical Microbiology and Infection, researchers took throat swabs and assessed the prevalence of meningitis-causing bacteria before and after the introduction of the vaccination program, using two studies cross-sections conducted nearly four years apart. They found that the vaccine significantly reduced carriage of meningococcal groups W and Y and maintained low levels of group C.

In 2015, in response to increased rates of meningitis cases caused by strains W and Y from 2009, the UK replaced a vaccine targeting only group C (introduced in 1999) with quadrivalent vaccines MenACWY . To take advantage of the effects of herd immunity, the vaccination program recruited adolescents between the ages of 14 and 19, where transmission of meningococcal bacteria is known to be highest.

One of the lead authors, Matthew Snape, who was a professor of pediatrics and vaccinology at the Oxford Vaccine Group during the study, said:

“These studies report the results of throat swabs taken from over 24,000 teenagers in over 170 secondary schools across the country, showing once again the fantastic enthusiasm of the British public to take part in research.

“The results show us that by immunizing adolescents with MenACWY vaccines, we are not only directly protecting them, but also reducing the risk of all other members of the community suffering from meningitis and sepsis due to these bacteria.

“Immunizing adolescents rather than infants means that we get more benefit from each dose administered. These two studies therefore provide invaluable data to help us use these vaccines effectively, both in the UK and internationally.

The researchers compared two studies – the UKMenCar4 study, conducted from September 2014 to March 2015 before the introduction of the MenACWY vaccine, and the Be on the TEAM study, conducted from March 2018 to November 2018 after the introduction of the vaccine.

Data from 24,062 students aged 15-19 were included: 10,624 from UKMenCar4 and 13,428 from Be on the TEAM. The researchers concluded:

  • C, W and Y meningococcal carriage decreased from 2.03% to 0.71%;
  • group W carry fell from 0.34% to 0.09%;
  • group Y carry fell from 1.6% to 0.5%; and
  • group C carriage remained rare (0.07% to 0.13%).

The results are consistent with data from the UK showing that the incidence of MenW disease has decreased in all age groups since the MenACWY vaccination campaign in adolescents; not just among teenagers themselves. Taken together, these data provide strong evidence for the need to target age groups with high rates of meningococcal transmission to best use these vaccines, and not necessarily immunize other high-risk age groups (e.g. infants), the researchers add.

Martin Maiden, Professor of Molecular Epidemiology in the Department of Biology at the University of Oxford, lead author of the paper, said:

“We have systematically studied meningococcal vaccination and its effects on carriage at Oxford since 1999. These studies have been crucial in enabling the most effective use of meningococcal vaccines worldwide.

“In combination with our work with colleagues at Public Health England (now HSA) who characterized the MenW epidemic variant at the genomic level, this work helped halt an outbreak that would likely have affected thousands of people. This demonstrates the importance of long-term studies which make it possible to anticipate epidemics and pandemics and to shorten them before they impact the population too severely.

Dr Tom Nutt, chief executive of the charity Meningitis Now, who played an important role in facilitating Be on the TEAM, said:

“Meningitis is a devastating disease that can strike anyone at any time and wreak havoc in its wake. Many young people will know someone in their community whose life, and that of their family and friends, has been torn apart by its impact.

“We are delighted to see that this important study has demonstrated such positive results not only for the health of young people, but also for the whole community. Now we need to redouble our efforts to encourage everyone who is eligible for their free MenACWY vaccination to take advantage of it.

Liz Rodgers, head of research at the charity Meningitis Research Foundation, who played a significant role in facilitating Be on the TEAM, said:

“We are delighted to have contributed to this important research initiative, which has provided evidence that the protection of the MenACWY vaccine extends to the whole population.

“With many teens across the country about to start or return to college, it is increasingly important to achieve a high rate of MenACWY vaccination, so we urge all teens and young adults to check that they are up to date with their routine vaccinations.”

The study was funded by the Wellcome Trust and the National Institute for Health Research (NIHR) Policy Research Program. The vaccine for one arm of the Be on the Team study (MenB-fHBP vaccine (Trumenba)) was provided free of charge by Pfizer to support research sponsored by independent investigators. Another vaccine (4CMenB (Bexsero) was provided by the Ministry of Health and Social Action.

Professor Nick Lemoine of the National Institute for Health and Care Research (NIHR) said:

“This NIHR-supported study has provided important data on the efficacy of MenACWY vaccines in inducing population immunity against meningitis – which has been shown to be effective in protecting all ages against this life-threatening disease. We would like to thank the incredible 24,000 participating teens who participated for their contributions.

Public Health and Mental Health Minister Dr Caroline Johnson said:

“This study shows why the MenACWY vaccination program is so important, enabling young people to protect themselves and in turn all age groups against this life-threatening disease.

“Vaccination remains the best line of defense against infectious diseases, including meningitis, and I encourage everyone who is eligible to take their free vaccine.”