KAWASAKI Disease AND CORONAVIRUS
Nearly half a century ago, Dr Kawasaki described the 50 cases
of the eponymous disease whose etiology continues to flummox us.
It has again reared its head in the alpine city of Bergamo in
Lombardy, Italy. Pediatricians in the busy Hospital Papa
Giovanni XXIII noticed a 30 times increase in the monthly
incidence of Kawasaki disease between February, 2020 and April,
2020 compared to the previous 5 years. They analyzed the
clinical data of these children diagnosed during the COVID19
pandemic and compared them to those diagnosed with Kawasaki
disease between January, 2015 and February, 2020.
They found that the children with Kawasaki diagnosed during this
pandemic had higher incidence of Kawasaki shock syndrome (50%),
meningeal signs (40%), macrophage activation syndrome (50%) and
abnormal echocardiography (60%). Seventy percent met criteria of
an abnormal Kobayashi score, which predicts IVIG resistance, and
needed adjunctive therapy with steroids.
Testing for SARS CoV-2 revealed positive IgG antibodies in 80%
but a nasopharyngeal PCR for virus was positive in 20% only,
suggesting an immune-mediated phenomenon. Coronaviruses have
been implicated earlier also as the etiological basis of
Kawasaki disease but had not been proven due to low PCR
positivity.
The study has put all pediatricians on high alert and may shed
light on the obscure origins of Kawasaki disease.
(Lancet Online May 13 2020)
A VACCINE AGAINST SARS-COV-2
The COVID-19 pandemic continues its relentless march across
the globe. It is clear we are in for the long haul. Consequently
the race for the vaccine is heating up. As of 28 April, 2020,
there are 90 contenders. At least six have started safety trials
in humans.
What is the modus operandi of the various vaccines? The
commonest approach is the protein subunit vaccine. There are 28
teams targeting the spike protein or its receptor binding
domain. The technique has been evaluated for SARS-CoV-1 in
monkeys. The downside of these vaccines is the need for
adjuvants and multiple doses. Twenty five groups are working on
the viral vector based vaccines. Here, attenuated viruses like
measles or adeno are genetically engineered to produce
coronaviral proteins. This approach has been successful in the
recently approved Ebola vaccine. However, sometimes previous
immunity to the viral vector may interfere with a robust immune
response.
Johnson and Johnson is experimenting with a killed viral vector
vaccine. And Codagenix, New York and Serum Institute, India are
working together to develop an attenuated live viral vaccine.
Human safety trials have already begun in Beijing using an
inactivated whole viral vaccine; some other groups are
attempting to make a nucleic acid based vaccine.
Unanswered questions include how rapidly these can be developed,
tested and clear safety trials. Who needs it most? What will the
costing be? Economics and politics will soon overshadow medicine
and ethics.
(Nature News 28 April 2020)
WHY IS SARS-CoV-2 KINDER TO CHILDREN?
Overall experience shows that children may be less severely
affected by SAR-CoV-2. This means understanding the disease in
children may be the key to mitigating the disease in adults.
The first hypothesis involves the differential expression of the
ACE- 2 receptors in children, through which the virus enters the
cell. However, ACE-2 also plays a crucial role in converting
angiotensin II to Angiotensin (1-7) and thereby attenuating its
damaging effects on the lungs and cardiovascular system.
Patients with chronic diseases have been noted to express less
ACE-2 receptors. Evaluation of ACE- 2 levels in children may
shed further light on the issue. The second possibility is that
the innate immune system in children may be more battle ready to
handle new organisms. Children have been shown to have natural
antibodies of the IgM isotype with a broad reactivity and
affinity independent of previous encounter with a particular
organism. Recurrent infections that children have and their
ongoing regular immunization may induce an enhanced state of
activation, which would result in more effective defense against
novel pathogens. There are data to show that children who were
immunized against measles, and also after influenza
vaccinations, had an overall reduction of other infections
besides measles or influenza.
(Eur Respir Journal 2020 Apr 23)