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1. US Security from Michael_Novakhov (88 sites): Eurasia Review: The Far-Reaching Consequences Of Measles Epidemic And Failure To Vaccinate


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The European Society of Clinical Microbiology and Infectious Diseases
(ESCMID) 5th Vaccine Conference will hear that the risks of failing to
vaccinate children may extend far beyond one specific vaccine, although
currently the most urgent problem to address is the resurgence of
measles.

Measles, a highly contagious infectious disease, is serious, causing
fever, rash and other symptoms in most children and complications
including pneumonia and brain inflammation. In 2018, across the globe
measles killed approximately 1 in every 75 children infected with the
virus, leading to over 100,000 deaths.

Furthermore, research by Assistant Professor Michael Mina, MD of
Center for Communicable Disease Dynamics at the Harvard T.H. Chan School
of Public Health and Harvard Medical School, Boston, MA, USA and
colleagues from his own and other groups suggests that infection with
measles in unvaccinated children increases their risk of other,
subsequent severe, non-measles infectious diseases in the 2-3 years
following infection. Thus, after surviving measles, children may fall
ill or die from other infections which they previously developed
immunity to, but this immunity was erased by the measles virus.

This observation, backed by numerous studies (with the mechanism
still being investigated) shows that when measles virus infects a
person, it primarily infects a large proportion of the memory cells of
the immune system. This results in so called immune-amnesia, whereby the
immune system cannot remember some of the diseases it has fought in the
past, thus exposing children to re-infection with these other diseases.

These findings would help explain the mysterious large drops in
mortality of up to 50% following the introduction of measles
vaccinations, even though prior to vaccines measles was usually
associated with much less than 50% of childhood deaths. This has gone
unnoticed in previous years because clinicians would not, for example,
link a death from another infectious disease back to a measles infection
that that child may have had two years earlier and that wiped away the
child’s immune memory for the other infecting pathogen.

“Prior to vaccination, measles infected nearly everyone. Because we
now think that measles infections may erase pre-existing immune memory,
by preventing measles infection through vaccination, we prevent future
infection with other infectious diseases allowed back into the body by
the damage done by measles,” explains Dr. Mina. “The epidemiological
data from the UK, USA and Denmark shows that measles causes children to
be at a heightened risk of infectious disease mortality from other
non-measles infections for approximately 2-3 years.”

He continues: “Prior to vaccination, the incidence of measles from
year to year could explain almost all of the variation in non-measles
infectious disease deaths that occurred over multiple decades.
Altogether, this suggests that measles may have been associated with as
much as half of all childhood deaths due to infectious diseases prior to
vaccination, and thus explaining the mysterious large drops in
mortality seen following introduction of the vaccine.”

He adds: “It may be that the only way for a child to recover from
this immune-amnesia is if their memory cells ‘relearn’ how to recognise
and defend against diseases they had known before, and they can do this
through re-exposure to the pathogen or by re-vaccination against that
particular infection.”

However, it is this re-exposure to the other pathogens that pose the
long-term risks following a measles infection. A recent epidemiological
study led by Dr Mina’s colleague, Dr Rik de Swart of the Department of
Virosciences at Erasmus Medical Center in Rotterdam, Netherlands looked
at the clinical outcomes of over 2,000 children infected with measles in
the UK (see link below). In that study, they found that children were
significantly more likely to require physician visits and had higher
rates of antibiotic prescriptions for 2-5 years following measles. To
mitigate these long-term effects, Dr Mina suggests “It might be
reasonable to consider re-vaccination with other childhood vaccines
following measles infection.” However, he adds that “because many
children who are infected with measles generally have not been
vaccinated, whether because of [parental] refusal or are in settings
that do not have access to vaccinations in the first place, this may not
always be a viable option.”

Thus – probably the most important conclusion of these fascinating
studies is that prevention of measles by vaccination is crucial and high
vaccination coverage is a fundamental step nowadays. However, in this
symposium, Helen Johnson, Expert in Mathematical Modelling at the
European Centre for Disease Prevention and Control (ECDC) Solna, Sweden
and Dr Takis Panagiotopoulos of the National School of Public Health,
Athens, Greece, will highlight that even when contemporary vaccination
coverage is high, risk of infection may be concentrated in certain
groups. Analysing data from Greece, they say that this heightened risk
can be associated with age (low vaccine coverage from previous years) or
social aspects (for example, barriers to access for the Roma
population, and vaccine hesitancy for healthcare workers or other
opinion groups).

The dangers of healthcare workers not being vaccinated are clearly
highlighted by these data. “The risk of being infected, and of onwards
transmission, is associated with the way people come into contact,”
explains Johnson. “Although only approximately 4% of cases were in
healthcare workers, an individual case in this group was far more likely
than any other to cause five or more secondary cases. In contrast,
approximately 30% of cases were in Roma children aged 4 years and under,
but each of these children caused, on average, only around one
secondary infection.”

Even if vaccination rates nationwide approach 95%, pockets of
susceptible unvaccinated people, such as the Roma population or
healthcare workers, may make outbreaks not only more likely but also
considerably larger than would be expected from assessments of
vaccination coverage alone. “The results highlight the imperative of
maintaining high vaccination coverage at all subnational levels and in
all population groups,” explains Johnson.

Data from ECDC show that a large epidemic of measles has affected
the EU/EEA in the past three years, with 47,690 cases reported between 1
January 2016 and 30 June 2019. Only eight countries — Romania (14,712
cases), Italy (10,439), France (5,812), Greece (3,288 c), United Kingdom
(2,412), Germany (2,240), Poland (1,874) and Bulgaria (1,295) — were
responsible for 88% of the cases in this period, but multiple cases
occurred in each of the 30 countries that report data to ECDC.

The burden of measles in the EU/EEA is particularly high among
infants and adults, the groups at the greatest risk of complications
following infection. Notification rates are much higher in infants and
children under 5 years than older age groups, however, a large
proportion (39%) of cases during this period occurred in adults aged 20
years and above, reflecting immunity gaps due to historic failures to
vaccinate in many countries. “Low uptake of vaccine in certain groups
means that, even in countries with very high rates of vaccination
coverage, re-establishment of measles is a concerning reality. It is
tragic and unacceptable that children and adults continue to die from
complications of measles, when safe and effective vaccines are readily
available,” concludes Johnson.

This ESCMID 5th Vaccines Congress, which will cover multiple
vaccine-preventable diseases is taking place just one week after WHO
announced that four European countries: the UK, Albania, Czech Republic
and Greece: had all lost their previous ‘measles-free’ status due to
confirmed endemic transmission in all four.

“Incidence of measles in the European Region increased in 2018
compared to previous years, and continues to escalate in 2019,” says Dr
Patrick O’Connor, Team Lead, Accelerated Disease Control Vaccine
Preventable Diseases and Immunization for the WHO-EURO region, who is
also speaking at this symposium.

He concludes: “Elimination of both measles and rubella is a priority
goal that all countries of the WHO European Region have firmly
committed to achieve. WHO urges health authorities to use every
opportunity to reach children with routine vaccination, as well as to
identify and close immunity gaps in adolescent and adult populations.”

Professor Ron Dagan, Ben-Gurion University of the Negev, Beer-Sheva,
Israel, the Chair of the Organising and Scientific Committee of the
ESCMID 5th Vaccines Congress adds: “Measles is definitively an imminent
danger worldwide that can be solved by aggressive vaccination policies.”

Eurasia Review

1. US Security from Michael_Novakhov (88 sites)