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Here’s a fantastic post I saw today!

The blog Shot of Prevention (at shotofprevention.com) has always produced first-rate material, but today it published an elegant post called How Do We Know Vaccines are Safe? which was informative, well-researched, and even beautiful to look at.    It goes through the phases of clinical trials needed for any drug approval (including vaccines) and describes the monitoring systems in place to assure ongoing safety of a drug after FDA approval.

In light of the ongoing Chinese vaccine scandals in the last few months, it is reassuring to see how different our system is from those of many other countries.

 

Everyone should check out this blog!

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Chinese Vaccine Uproar

This week news broke that a large China-based vaccine manufacturer called Changsheng Biotechnology Co. had both produced “unsafe” DTP vaccine and had falsified records of production of a rabies vaccine.  See the WSJ story here:

Also, see an update from 7/30/2018 here:

None of these applies to the U.S. vaccine supply; these were all for in-country use and were sold to local provincial governments within China.  In the U.S., every biotech company’s products, including vaccines, must be separately submitted for approval through a lengthy process before they can be sold.   We also have very vocal consumer advocates and social media which are quick to call out deficiencies in the drug manufacturing realm.

Health scares in China, like every large country, are not rare.  Just as we have had the lead in Flint, MI, several years ago China had the scandal of thousands of dead pigs found floating in rivers used for irrigation and for drinking water.  More recently, melamine found in Chinese milk products, infant formula and pet foods made headlines by causing kidney failure and deaths in both humans and pets.

Physicians in Hong Kong with access to international vaccine supplies, are expecting a surge in patients from mainland China seeking safer vaccine choices:

 

 

Rotavirus Vaccine

Diarrhea is a very serious problem throughout the world.  You might not know it if you live in the US, but diarrhea is the #2 cause of death in the world for children age 5 and under.  Here we have great treatments for diarrhea – clean water, electrolyte solutions, and IV rehydration.  But in the developing world, these are all in short supply, and many children die of diarrheal illness without even getting to a hospital.

There is also a vaccine for one of the leading causes of severe diarrhea, called rotavirus infection.  Rotavirus vaccine, now used in most developed countries, has dropped the death rate from diarrheal disease in children tremendously.  However, the vaccine is not available in many areas of the world, and has a complicated history in the U.S.

The original version of the rotavirus vaccine, called Rotashield, was licensed in 1998.  It was pulled off the market after several months when an association was noted between getting the vaccine and developing a condition called intussusception, an intestinal blockage.   Vaccine manufacturers were eager to replace it but had to run many trials to be sure that newer products did not cause the same side effect.  It took until 2006 for the first replacement  (called Rotateq) to get licensed.  2 years later, Rotarix was also licensed by a competitor.  Bother are oral vaccines, and are normally given at the same time as other vaccines.  Each vaccine requires a different number of doses.  Both have been extensively evaluated and do NOT cause intussusception.  We are thrilled to have less babies in the emergency room receiving IV fluids!

Next task is to get this vaccine cost down for the parts of the world where it is too expensive to use routinely.


Dosing in the U.S.:

For Rotateq:

  • 3 doses, given at 2 months, 4 months, and 6 months of age

For Rotarix:

  • 2 doses, given at 2 months and 4 months of age

Lyme Disease and the Vaccine No One Wanted (until now)

If you live in the Northeast, Lyme Disease is a hot topic right now.  We are seeing a lot and will be seeing more.

Lyme Disease, transmitted by deer ticks, is a difficult illness.  The ticks are tiny, and many who are bitten never even notice the tick attached to their body.  This is especially true for children.  Some people get infected and have no symptoms; some develop only a rash  which goes away (and nothing more), or one can develop more serious effects, from joint pain and swelling (especially in the knee) to neurological symptoms.   Treatment ranges from 2 weeks of an oral antibiotic (for the rash, called “erythema migrans”) to weeks of intravenous antibiotics (for brain and spinal fluid infection).  There is also a single-dose prophylactic treatment in those over 8 years old who get a suspicious tick bite to prevent symptoms from occurring.

Of course, it is much preferable to prevent tick bites in the first place.  This is done by using an effective insect repellent (preferably DEET-based) and by minimizing exposed skin (i.e. tucking pant legs into your socks, etc).  It is also highly recommended to do a daily “tick check” from head to toe after visiting risky areas to find and remove any ticks in the first 24 hours, before they have the chance to transmit disease.  (Also, see below on treating your clothes with permethrin).  But best of all would be a vaccine!!

I am asked almost every week in the summer why we don’t have a vaccine to prevent Lyme Disease.  Well, we did – it was called LYMErix, licensed in 1998.  Protection against Lyme Disease at around 80% after 3 doses was not 100%, but it was better than nothing (and was way better than current flu vaccine protection, for example).  But a vocal consumer group got a lot of press by touting a laundry list of supposed side effects and sales never took off.  Eventually the manufacturer (now known as Glaxo) took it off the market after only 3 years the because of such low sales that they were losing money on making it.  They have no plans to restart production, although Baxter Vaccines has a candidate vaccine they are considering enrolling in clinical trials.  Good luck with it!

Here’s a story from NPR on keeping deer ticks away with permethrin spray:


Dosing for Lyme vaccine: N/A (no longer on the market)

DTaP/Tdap/Td vaccines – which is which?

There is often confusion between the different vaccines that protect against tetanus, diphtheria and pertussis.  DTaP, Td, and Tdap are all different vaccines, and they are used in different populations, from infancy to older adulthood.

A quick primer on the alphabet:

  • D is for diphtheria – an illness caused by Corynebacterium diphtheriae, the symptoms involve cough and fever and can progress to cause difficulty breathing by what is called a “peudomembrane” developing in the throat.  Most common in children; spread by one who has it coughing in proximity to others who are susceptible.  Occasionally it can be fatal.  Nowadays diphtheria is rare in the U.S.
  • T is for tetanus, also called “lockjaw” by my grandparents, this is a bacterial infection caused by Clostridium tetani.  Most people think of this as a wound infection (for me it brings to mind the “stepping on a rusty nail” image).  Also can contaminate canned foods.  Can cause severe and painful muscle contractions of  most muscle groups.  Go to the ER with a dirty wound, and you’ll commonly leave after a tetanus booster if you are not sure of your last dose.  Uncommonly seen nowadays because the vaccines are so effective against tetanus.
  • P is for pertussis – an under-recognized illness, characterized by a severe or prolonged cough.  In the unvaccinated patient usually there is high fever but in many who have received the vaccine it causes an annoyingly persistent cough that can go on for weeks or more.  Besides a persistent coughing illness in older children, pertussis is well known to infect newborns, and in them it can be very serious, especially in babies under 2 months old, who can develop apnea and respiratory failure and even death.  For this reason women receive an extra dose of a pertussis-containing vaccine with each pregnancy (see below).

 

DTaP is the vaccine used in infants and children up to 6 years old.  Vaccination starts at 2 months old, and is normally given at 2, 4, and 6 months of age, with a booster dose at age 4-6 years.  For the very young, pertussis (the “P”) is a key part of the protection, as pertussis can be life-threatening in newborns.  The prior version of this vaccine, called DTP (no “a” for “acellular” pertussis) was very effective but caused a lot of high fevers and behavioral changes and was phased out starting in 1998.

Tdap is the version given at age 11 years; only once (for now) unless you are a woman and become pregnant – then you get an additional with each pregnancy (see above).  Protection lasts 10 years against tetanus BUT we know that the pertussis protection wears off much earlier.  Someday this is likely to be replaced by a more effective version that gives more pertussis immunity. 

Td (tetanus and diphtheria components only) is the version that adults get every 10 years, or after 5 years with a “dirty wound”.  May be replaced by Tdap in the future if a more effective version of it gets approved.


Dosing:

Infants and young Children receive DTaP:

  • 2 months old
  • 4 months old
  • 6 months old
  • 12-15 months old
  • 4-6 years old

 

Preteens receive Tdap:

  • 11 years old (once only)

 

Pregnant women receive Tdap:

  • in the 3rd trimester of EACH pregnancy

 

Everyone else who has received one dose of Tdap already receive Td:

  • every 10 years for life

RSV Vaccine – there still isn’t one…(yet)

Respiratory Syncytial Virus, or RSV for short, is a viral infection that causes a mild respiratory disease in many infants and toddlers and more severe disease in a few, especially in premature infants.  It circulates during the winter and is quite contagious, being spread by respiratory droplets and infected surfaces to susceptible patients.  Many parents have brought their infant or toddler to their doctor with symptoms of cough, congestion and wheezing, finding out that their child has what we call “bronchiolitis.”  RSV is one of the largest causes of bronchiolitis.  We rarely do tests to confirm which virus is causing these symptoms, so for most pediatricians RSV and bronchiolitis mean the same thing.

The most severe complication of RSV is that in very young infants (under 2 months old) and in preemies, RSV can trigger respiratory failure and apnea (cessation of breathing).  These can result in hospitalization for mechanical ventilation, oxygen therapy, intravenous nutrition and often prolonged hospital stays.  Weeks or months of intensive care can run up hospital bills into the hundreds of thousands of dollars.  For older infants and toddlers, RSV is usually not so severe, but can occasionally lead to hospitalization for oxygen therapy alone while the disease runs its course.  A lesser-known fact is that RSV also strikes older people, and causes a large number of deaths and cases of pneumonia among the elderly, especially those who live in nursing homes or other group settings.  Exposure to the virus occurs when babies and children with RSV visit their elder family members, who become infected and then in turn infect their peers.

Currently, there is a preventive treatment for RSV that is fairly effective but is also very expensive and inconvenient.  The medication is called Synagis – an injected synthetic antibody specifically developed to combat RSV.  Unlike a vaccine, which stimulates the body’s immune system to make natural antibodies to fight off an infection, Synagis is an artificial antibody, which has to be given repeatedly because its levels start to drop soon after injections are given.  The problem is that it has to be given by injection each month during RSV season, and the cost is huge: a single month’s dose can cost $1500 or more, and it is typically given for up to 5 months in a row (November through March) to patients, who must qualify for the treatment to assure insurance coverage.  Also, the need to come to the doctor’s office monthly is less than ideal.

Understandably, the quest for an RSV vaccine is a large focus of pediatric research dollars, as a preventive therapy would pay off many times over in dollars saved.   Several companies have clinical trials in progress seeking to develop an effective vaccine against RSV.  Unfortunately, this is an old and sad story, as there have been many candidate vaccines for RSV over many years without a single viable result.  The company that makes Synagis (AstraZeneca) is also seeking to improve it, so that it will last longer (and remain under patent protection).  The case for a vaccine to prevent RSV is obvious – it would save lives, prevent some very expensive hospitalizations, and if given universally, would eliminate a large source of illness during the winter months among the very young.  This is turn would keep kids in daycare and keep parents at work.  The only losers would be pediatricians’ offices, since we would be less busy during RSV season.  I for one would be happy for the decreased business!

Prevnar13 vaccine – great protection for the young and the old(er)

Newborns have a lot going against them.  They need a lot of love, attention, feeding, changing, and innumerable other things to be done for them.  They are also pretty terrible at fighting off some kinds of infections.  Almost any infectious disease can infect newborns.  They remain at risk until either they are exposed to it, (hopefully) survive intact, and make antibodies to it, OR until they are effectively vaccinated.  For many of the worst infections that can attack newborns, we now have effective vaccines.  There are, of course, some notable exceptions (HIV, RSV are two of the biggies).  But one type of infection that used to scare parents and doctors alike was bacterial meningitis.  There are several types of bacteria that can commonly caus meningitis, but the two most prevalent in the pre-vaccine era were Haemophilus influenzae Type B (aka HiB) and streptococcus pneumoniae (aka strep pneumo, or pneumococcus).

A vaccine was developed against HiB meningitis in 1985, which led to a race to also protect against strep pneumo meningitis.  In 2000, a vaccine was licensed for use during infancy that protected against 7 strains of strep pneumo.  It was called Prevnar.  It was a great success, and an improved version was introduced in 2010, which added protection against 6 more strains, and the new product was called Prevnar13.  Since the original introduction of Prevnar, the number of infants stricken with pneumococcal meningitis has dropped off a cliff.

Prevnar is a great success because it is able to protect infants against a very serious disease with very few doses.  Most infants have protective levels after only 2 doses, which are given at 2 and 4 months of age.  The other 2 doses, at 6 and 12-18 months of age, boost immunity even further.

 

Look, a bonus for grandparents, too:

Prevnar13 is now also used in the elderly (sorry, my parents hate that word, but it’s what everyone uses for people over 65 years), along with another (different) pneumococcal vaccine, called PPSV23.  Even my parents have gotten it – they call it the “pneumonia vaccine” because in older adults, pneumococcal infection most commonly causes pneumonia.


Usual Pediatric Schedule:

  • Primary series at 2, 4, and 6 months old
  • Booster Dose at 12-18 months old