sábado, 27 de julho de 2013

Rotavirus, Pneumococ and Meningococ vaccines

In Poland there are 3 recommended vaccines which are not part of the vaccination program, so I decided to study to see what are the benefits, costs and potential risks of these vaccines and decide if they are worth taking. One should note that Rotavirus and Pneumococ at least are part of the vaccination program for all children in Brazil.


Pneumococ

Pneumococ is a bacteria which is a leading cause of Pneumonia (40% of pneumonia cases are caused by Pneumococ in Brazil), thought there are many others. There are 80 known sub-types of pneumococ, being that 23 of them are known to cause pneumonia. There are vaccines which cover 7, 10, 13 or even all 23 of the most common and dangerous pneumococs. Pneumococ can also cause meningitis. See the section for meningococ to see what is meningitis.

One particularly relevant thing to think about is that the pneumococ is increasingly resistent to antibiotics. In only 3 years the amount of pneumococ samples found to be resistent to 3 or more classes of antibiotics grew from 9% to 14% and those resistent to penicilin from 21% to 25%. The resistence was specially high among young white children, as those usually receive more antibiotics than other groups. Source here. That's why the vaccine against pneumococ is increasingly important.


Pneumococ - How this vaccine is made and Risks

Pneumococ vaccine is made with dead or severely weakened pneumococ bacterias. Aproximately 35% of people vaccinated against pneumococ present a side effect, which usually disappear in 2-3 days. The common side effects are an increase in body temperatyre, pain, nauseas, weekness feeling. A red area where the injection was applied can also appear. There is a chance of 1 in 10 million that the pneumococ will reactivate and attack the patient.



Pneumococ Vaccine - costs


Costs 326 zł each application in Medicover, 4 are required. I read that the Brazilian government pays R$50 each application (75zł) and the american government only US$2,5! So it would be much cheaper for me if the government covered the cost. This also shows the monetary inneficiency of non-public health system, if a private person has to pay over 5 times what the brazilian government pays, or 30 times what the USA government pays. I wonder it is so much cheaper in the USA, maybe it is only produced there and needs to be transported by plane with refrigeration everywhere else?


Pneumococ Vaccine - benefits

Pneumococ is relatively rare in Poland, with an infection rate of aprox. 30/100 000 source here So we can say that the vaccine has an accumulated chance of avoiding a pneumococ infection of aprox. 0,1% in Poland.


In Brazil the disease is more common, and my calculated chance of the vaccine saving the life of a child is aprox. 0,4%. Mandatory vaccination in Brazil decreased the number of deaths of children due to pneumonia, meningitis and acute otitis from 11200 per year to 9000 per year, and also significantly decreased hospitalizations. It decreased the cases of pneumonia from 365 000 to 295 000 and of meningitis of 587 to 171. These cases are only the cases among children. source here

Probably not very useful for the decision of parents, but: There is also a cross-benefit across the entire society, vaccination decreases pneumococ infection among children, so children in turn infect less people over 50, which decreased the rate of deaths because of pneumonia among people over 50. And there is also a secondary benefit for the entire health system, as each avoided hospitalization saves R$5000 (=7500 zł) in costs for the health system due to used hospital beds and exams. In the private sector the cost savings are higher due to the higher costs in the private sector.

Meningococ

Meningococ is a bacteria which can cause meningitis. It has many subtypes: A, B, C, Y e W135. In Poland the most commons are B and C. It is very rare, but devastating with a very high chance of death (20%) and a very high chance of leaving permanent damage. In Poland for children of 0-11 months the rate of meningococal infection is 14/100 000 (= 0,014%), for children with 1, 2 and 3 completed years the rates are respectively 7, 6 and 5 per 100 000 source here

Meningitis

Meningitis is an infection of an area of the brain and it can be caused by bacteria, fungus, virus, etc. It is devastating with a very high chance of death (20%) and a very high chance of leaving permanent damage.
90% of bacterial meningites are caused by 3 agents: Haemophilus influenzae b (Hib), Neisseria Meningitidis (meningococo) e o Streptococus pneumoniae (pneumococo). Note that here in our list we have vaccines for 2 of those.
A child with meningitis can progress to 3 possible scenarios:
  • Infection is defeated without leaving permanent damage
  • Infection is defeated but it leaves permanent damage, for example: brain paralisis, loss of vision, loss of hearing (at least 40%)
  • Death (20%)
I think that showing some particular cases can help understand how those scenarios might appear.

Case 1 -> Child in Brazil, full description here


The mother is addicted to drugs. The child was born with 36 weeks, with 2150g and Apgar 5 in the first minute, 7 in the 5th and with hidrocefalia (abnormally big head filled with liquids). Had a cirurgy to correct the hidrocefalia, but in the cirurgy acquired bacterian meningitis which lead to total loss of vision and brain paralisis. With 6 months the baby cannot sit. I guess it is convincing enough to vaccinate against agents which might cause meningitis for any child which might have cirurgy.


Case 2 -> Meningococ case in New Zealand, full description here


Basically the case could have been prevented if the child had been vaccinated, the bacteria was acquired in an epidemy of meningococ in New Zealand, thought it is present in all countries at low rates. The meningococ infection lead to amputation of both arms and both legs. I guess this one is enough to convince that meningococ is a terrible bacteria.

Meningococ Vaccine - How it is made and risks

The Meningococ vaccine is made with parts of the capsule of meningococ (Polysaccharide and for subtype B also protein), therefore I believe that it does not have any risk of reactivation of the virus, since it has no genetic material. On the other hand, this vaccine does not generate T memory cells, so it's protection disappears after 4 years. I suppose that they considered maningococ too aggressive (see the description of meningitis above) to risk a reactivation of meningococ and therefore decided for this safer, but not so long lasting, solution. The only listed possible risk that I found is fever after taking the vaccine.



Meningococ Vaccine - costs

This is the cheapest one, listed at 142 zł in Medicover for each application. 2 are required.


Meningococ Vaccine - benefits

The accumulated chance of infection by meningococ up to 4 years is 0,03%. Since meningococ is such an extremely dangerous agent, we can consider that the chance that the vaccine will save the child's life (or vision, or hearing, or brain, etc) is 0,03%.

Rotavirus

Rotavirus is a virus which causes diarrea, vomits and fever. It is very common, with data saying that up to 95% of the children in Poland will have it until they are 5 years old and 65% of those up to 2 years old. source here The treatment to avoid death by diarrea is simple, it just requires keeping the child hidratated.

Rotavirus - Transmission and how to avoid

Rotavirus is transmitted via touching feces and not washing the hands properly then infecting via the mouth, or also by direct contact between people, also by contaminated objects, water and food.


To avoid it one should give the child only milk, sterelize all objects which the child uses, wash the hands very well, etc.


The transmission is very easy, so even while taking all cares there might be infection, specially if the child has contact with many different people (such as in school).


Rotavirus vaccine - How it is made Side effects

The vaccine is made with live atenuated virus. The rotavirus vaccine has similar side effects as an actual infection by the virus, and those are considered frequent (more than 10%): diarrea, vomits, fever. It seams that the RotaTeq has more collateral effects. A previous variant of the vaccine was known to cause in some children "invaginação investinal", in english "intussusception" an intestine disorder which might require cirurgy. But with Rotarix this is either not present at all (according to some sources) or rare in other ones. sources here and here and here

Rotavirus Vaccine - costs

Rotarix is monovalent (protects against 1 subtype) and the Brazilian government pays R$18 for each (27 zł). In Medicover it costs more than 300 zł each.

Rotavirus Vaccine - benefits

Rotarix protects at a 70% rate (against the most common virus variant, responsible for 75% of infections) and RotaTeq at a 74% rate (contains 5 virus variants) against rotavirus infections. It is estimated that the introduction of Rotavirus vaccines in Brazil saves 850 lives per year, thus giving a chance that the vaccine will save a child of 0,14%.

In the European Union, the chance of hospitalization per year for children due to Rotavirus is 1 in 54, so almost 2%. The vaccine has a 70% chance of avoiding this, so around 1,5% chance of avoiding a hospitalization. source here


Conclusion

Because of the risk of meningitis and pneumonia I'd recommend vaccinating at least for pneumococ and meningococ, specially so if you think the child might have a cirurgy in it's first 2 years. As for Rotavirus I'm still not 100% decided due to the risk of intestinal problems, but I think it is also positive, thought I'd rather apply it as late as possible. The first application is from 6 to 12 weeks, so I'd rather apply with 12 weeks.

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