New meningitis vaccine achieves high protection in babies up to two years

A vaccine against meningococcal meningitis showed high protection in babies up to two years old for the four types of bacteria most common in this age group and who had never had contact with the pathogen.

The vaccine induced an immune response similar to that of the existing formula, known as monovalent against meningitis caused by meningococcus C, and also showed high protection compared to the quadrivalent vaccine also already in use, which protects against types A, C, W and Y. .

Meningococcal meningitis causes inflammation of the meninges, the membrane that surrounds the nervous system, including the brain. Symptoms are often nonspecific and include weakness, fever, vomiting, and headache. In more severe cases, it can lead to hospitalization and death.

The results of the phase 3 clinical study that evaluated the non-inferiority of the immunizer compared to the other two were published on the 21st day in the specialized journal Human Vaccines and Immunotherapeutics.

According to pharmaceutical Sanofi, the vaccine under study, called MenQuadfi (MenACWY-TT), is innovative for inducing a superior immune response to meningococcal type C compared to other mono and tetravalent formulas, from pharmaceutical Pfizer. Meningococcal C is the main causative agent of invasive meningococcal disease in Brazil (it corresponds to about 80% of the types of meningococcal meningitis in the country).

In addition, the immunizer proved to be safe, without the occurrence of serious adverse effects.

To assess the immune response to the new formula, the researchers recruited 701 babies aged 12 to 23 months, who had not received any previous meningococcal vaccine, at 29 centers in Germany, Denmark and Finland.

Of the total number of babies, 230 received the MenQuadfi vaccine, 232 received the quadrivalent vaccine from Pfizer and 239 received the monovalent vaccine against type C. Blood samples were taken on the first day before vaccination and 30 days later to evaluate antibodies produced.

According to Isabelle Bertrand, deputy director of medical affairs for vaccines at Sanofi Europe, this is the first study that has demonstrated a quadrivalent meningococcal vaccine having a superior immune response in previously immunized children compared to an available monovalent vaccine.

“Meningococcus C is currently the one that causes most meningococcal meningitis in Brazil, but a significant increase in the incidence of meningitis caused by the more aggressive type W has also been observed in the last ten years. Given the unpredictability of the type in circulation, it is important further expand protection against the four main types [A, C, W e Y] disease,” he said.

What’s more, when evaluated three years later, 100% of the children immunized with MenQuadfi still had antibodies — up from 6 out of 10 achieved with the quadrivalent vaccine.

In Europe, where the studies were carried out, the most commonly used vaccine is Pfizer’s quadrivalent vaccine, but this same vaccine has less protection against type C. Recently, the UK and the Netherlands have had outbreaks of the disease in a more aggressive way. of meningococcus C, whose protection in the population was lower due to vaccine leakage against this type.

Thus, national immunization programs began to adopt the option of immunization with the monovalent C vaccine in the first two years of life and, later, with the quadrivalent form in adolescence.

Here, the National Immunization Program offers the monovalent C vaccine in the child’s routine schedule, with three doses of the conjugated version at three, five and 12 months (reinforcement). The form against meningococcus B is offered to babies in the private network. The quadrivalent form has been offered in the public network for 11 and 12 year olds since 2020.

According to the pharmaceutical company, MedQuandfi already has authorization for use in children over 12 months of age in Brazil.

According to pediatrician Marco Aurélio Sáfadi, professor at the Faculty of Medical Sciences at Santa Casa de São Paulo and president of the infectology department at the Brazilian Society of Pediatrics (SBP), the new vaccine has the advantage of a very robust immune response, which has also been shown to longer lasting in studies, which may indicate that it will be more effective in babies up to two years old in terms of protection against type C.

“This higher antibody rate is likely to translate into longer-lasting protection, protecting children for longer and against different forms,” ​​he said.

For him, despite being a rare disease, with an incidence in the population of about a thousand cases per year (in the pre-pandemic period), meningitis causes fear because it can evolve into serious forms in a few hours. According to the Ministry of Health, in 2022, 11 deaths have already been recorded in children and young people aged zero to 19 years. In 2021, there were nine deaths in total, and in 2020, 51.

“Most of the time, it affects healthy children, without any previous condition, and can progress to a serious condition with hospitalization and even life-threatening in a few hours”, he says. “Therefore, it is very important to maintain a high vaccination coverage rate to protect all children.”

According to the pediatrician, diseases of respiratory transmission, such as meningitis, had a reduction in incidence during the pandemic due to isolation and the fact that children have been many months without attending schools. Now, with the return, it is possible to see a resurgence of cases, he says.

“We’ve seen a reduction of about two-thirds of the cases that we’d normally see. But there’s definitely a need to increase protection now, especially for those who haven’t been vaccinated in the last two years, to prevent further outbreaks.”