(Left) WHO SAGE Senior Health Advisor Dr Joachim Hombach and WHO Director of Immunization Dr Kate O’Brien present new recommendations for RSV, rubella and polio vaccination.
For the first time, WHO has recommended that pregnant women be vaccinated against respiratory syncytial virus (RSV) or that newborns be given monoclonal antibodies to protect against severe RSV disease. This virus is making a comeback around the world due to the spread of the new coronavirus. 19 The pandemic has subsided.
In 2022-2023, after two seasons of low prevalence, likely due to pandemic-era public health restrictions, RSV became the second most commonly detected virus after SARS-CoV-2 (22%). 10.9%).
New guidance on respiratory syncytial virus, polio vaccination and another new recommendation aimed at accelerating the pace of rubella vaccination in under-5s, both of which were announced at a press conference on Wednesday by the WHO Published by the Advisory Group on Immunization Strategy (SAGE).
The guidance ran counter to data showing that routine vaccinations in 2023 still have not kept pace with pre-pandemic levels.
“In 2023, 14.5 million children will not have received at least one vaccine dose,” WHO expert Kate O’Brien, director of WHO’s Department of Immunization, Vaccines and Biology, said at a briefing. “Before the pandemic hit, that number was 12.8 million children. Therefore, the world has not returned to the performance that was already achieved before the pandemic hit.
Willingness to vaccinate children with ‘zero dose’ lags globally, but progress is being made in Africa
Africa was one of only two WHO regions to actually reduce the number of “zero-vaccination” children who would not receive any vaccination in 2023.
This also leaves the Gavi Vaccine Alliance unable to meet its goal of reducing the number of children receiving a “zero dose” by 25% by 2025, the alliance said yesterday in its annual progress report, also published on Wednesday. Ta.
However, it was good news for the African region. Africa was one of only two regions in the world to see a decline in the number of zero-dose children not vaccinated in routine immunization programmes.
“In fact, the number of children receiving zero doses in the African region decreased in 2023 compared to 2022, which is really good news,” O’Brien said.
“Additionally, the African region was also one of a limited number of regions where the number of children who did not receive measles vaccination decreased, compared to 12.2 million children in 2022. has fallen to 11.5 million,” O’Brien said.
Global progress in HPV vaccination
Girls wait to receive HPV vaccination at an elementary school in Masaka, Rwanda. In 2023, Africa had the highest HPV vaccination rate in the world.
Both the SAGE and Gavi reports also point out that significant progress has been made in eliminating cervical cancer by vaccinating 14 million girls with the HPV vaccine.
O’Brien said Africa was also notable for seeing the fastest growth in immunization rates of almost any other region in the world.
“With Gavi’s support, 14 million girls have been vaccinated against HPV, more than in the last 10 years combined,” Gavi said in a press statement. “Gavi is currently helping to prevent more than 600,000 future deaths from cervical cancer alone and is on track to reach 86 million girls by the end of 2025.”
There are two options for RSV recommendations
In May 2023, GSK’s Arexvy vaccine was first approved for use against respiratory syncytial virus (RSV), and the WHO now recommends it for pregnant women.
The RSV recommendations for countries consist of two parts. One is to introduce new RSV into pregnant women during the third trimester to protect the fetus from congenital RSV and prevent neonatal disease. Alternatively, countries could choose to give newborns themselves a single dose of monoclonal antibodies, the SAGE panel recommended.
There are advantages and disadvantages to each approach. Obtaining RSV monoclonal antibodies remains very expensive. However, the vaccine’s clinical trials have also shown a safety “signal” of a slight increase in preterm births among vaccinated women, but the increase was very small and the increase was very small when the mother received the vaccine. The increase in neonatal survival was greater.
“Nearly 97% of (RSV)-related mortality is estimated to occur in low- and middle-income countries,” said Dr. Hanna Nohinec, Chair of the Immunization Experts Strategic Advisory Group. “After 60 years of waiting, we now have two interventions to prevent RSV in children: vaccination of the mother and subsequent monoclonal antibodies to the infant.
“Mr Sage said all countries should introduce passive immunization to prevent severe RSV disease in children, which could be carried out either by maternal vaccination or by this monoclonal antibody. Recommended.
“Vaccine efficacy studies have documented disproportionate preterm birth safety across the two trial sites that administered maternal vaccinations, primarily in South Africa and Argentina, and SAGE investigated this signal. However, the risk “When you take into account the results and benefits, it’s clear that there are significant benefits to be expected,” she said, adding that researchers will continue to collect more data on the issue of preterm birth.
Rubella vaccination is recommended even if measles vaccination coverage is not optimal
Infants in Rwanda receive combined measles and rubella vaccine. WHO currently recommends that rubella be included in routine immunizations, even in countries with measles vaccination shortages.
In important but technically sensitive advice, SAGE also recommended that countries administer rubella vaccine “universally” even if measles vaccination coverage has not reached 80%. .
Approximately 32,000 infants are born with congenital rubella syndrome each year. Congenital rubella syndrome is an insidious disease that causes severe heart defects and intellectual disability. Most of these cases have occurred in just 19 countries with historically low overall vaccination rates.
Under previous WHO recommendations, countries should achieve 80% coverage with at least the first dose of measles vaccine, and measles was used as a proxy for national immunization coverage capacity.
In countries with low overall vaccination coverage, the introduction of rubella vaccine may actually increase the overall environmental exposure of girls and pregnant women to the rubella virus, which may result in further increases in neonatal CRS cases. This was due to concerns.
However, new modeling work and analysis has shown that the 80% threshold rate is “overly conservative and is no longer justified,” SAGE experts said in a press statement.
Six of the remaining 19 countries that have not introduced rubella-containing vaccine (RCV) are currently planning to do so, and SAGE recommends that the remaining 13 countries also do so.
“Universal implementation of RCV should also begin in the remaining 13 countries, with campaigns targeting a wide range of age groups at the time of implementation.In countries with regular MCV coverage below 90%, Regular follow-up campaigns are recommended,” SAGE said.
polio vaccine
A September campaign to vaccinate children with oral polio vaccine in the conflict-torn Gaza Strip reached 90% coverage target. WHO now also recommends injecting inactivated viruses if possible.
SAGE is also administering inactivated poliovirus (IPV) jabs along with oral polio vaccine (OPV) to better immunize at-risk children during polio outbreaks and subsequent vaccination campaigns. recommended that you do so.
The additional shots will protect against environmental exposure to vaccine-derived poliovirus in outbreaks like the one recently seen in Gaza, as well as exposure to wild poliovirus, which is still circulating in countries such as Afghanistan and Pakistan. It will provide good protection, the WHO said, adding: “As long as it does not affect the timeliness of the response.”
WHO and national partners are currently in the process of phasing out bivalent OPV and replacing it with new OPV vaccines that do not mutate easily in the environment and cause new infections in other infants.
However, two doses of OPV are required to build up the necessary immunity, and undernourished children have a weaker response. On the other hand, recent studies have shown that IPV responses are enhanced in the gut to OPV vaccines, regardless of which type is administered. Protecting against paralysis, the most serious consequence of polio, is a boost for children who are commonly at risk.
“The whole idea here is to move to a world where we don’t administer oral polio vaccines, but we’re still relying on injectable vaccines in the final stages of polio eradication,” O’Brien pointed out. He said so. This change has already occurred in most developed countries, and IPV is the only vaccine that infants and young children are already receiving.
“Therefore, including the injectable polio vaccine along with the oral polio vaccine whenever an epidemic occurs, and including the injectable polio vaccine in prevention campaigns whenever possible, is a kind of second-hand approach to strengthen immunity. It provides significant protection and protects against the possibility of circulating strains of the virus (from the vaccine) that can turn into a virus that causes paralysis.”
Weigh the costs, benefits, and scientific evidence of vaccines
All of WHO’s recommendations concern not only the cost of vaccines, but also the nuanced considerations of benefits and knowledge gaps that countries should take into account in their decision-making.
“Fifty years ago, there were seven diseases for which vaccines currently exist. Today, there are more than 30 diseases that can be prevented by vaccines. And over the past 15 to 20 years, there has been a great success rate in vaccine development,” O’Brien said. “There are now more vaccines available than any country can accept,” he said.
And more and more vaccines are being developed all the time, especially with the recent introduction of new technologies such as mRNA.
Countries are therefore being forced to weigh an increasing number of factors, including scientific evidence and data on the relative costs and benefits of different options.
“So we’re really in a new era of vaccine development and vaccine deployment,” she says. “However, achieving the ultimate endpoint of disease prevention, the most equitable kind of disease prevention we will ever achieve, depends largely on the characteristics of the disease and the characteristics of the vaccine for that disease. It depends on the complete eradication of the disease.
However, increasing vaccine options also mean that more and more countries are struggling with questions surrounding the evidence of vaccine benefit relative to cost, while many of the latest vaccines and solutions , it may remain unavailable until the price drops.
And that typically only happens when vaccines become available in the public domain in generic form, or when institutions like Gavi procure them in bulk on behalf of low- and middle-income countries, resulting in , the price will also go down.
“Vaccines are not a preventative measure unless they are actually used,” O’Brien said. “So this is at the heart of the vaccination program: getting the vaccines to the countries that need them.”
Image credit: Flickr – UNICEF Ethiopia, University of Oxford/Tom Wilkinson, UNICEF, NIAID, WHO, WHO.
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