Vaccinology 2016: A New Era of Immunization

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I attended the Vaccinology 2016: A New Era of Immunization. It was a forum on the importance of vaccination and its recent advancements. I joined the forum because I love Immunology and there's a free quadrivalent influenza vaccine after attending the forum. Congratulations to the Mu Sigma Phi Sorority for organizing this event. Even at this age, there are still a lot of people doubting the safety and efficacy of vaccines. These misconceptions were formed because of lack of information. This is why forum like this is a great avenue to correct all the misconceptions and inform the public so they can decide based on scientific and clinical facts and not based on fear brought about by the wrong information.

Dengue, Now A Vaccine Preventable Disease

The seminar started with the talk of Dr. Anna Lisa Ong-Lim, a pediatric infectious disease expert at the Philippine General Hospital. Dr. Ong-Lim talked about the new dengue vaccine which was recently administered to children nine years old and above here in the Philippines. She said the the dengue vaccine was already submitted in approximately 20 dengue endemic countries. Philippines was the second country to approve the use of the new dengue vaccine next to Mexico. This dengue vaccine was started in Mahidol University in Thailand and it took about 20 years before it was made available for public use. The vaccine is a tetravalent vaccine capturing all four dengue strains. The vaccine is a recombinant dengue vaccine with yellow fever virus as the backbone mixed with the four dengue virus serotypes. 

The main goal of this vaccine was to prevent dengue diseases caused by the four dengue serovars in individuals 9-45 years old and above and living in endemic areas. This dengue vaccine is composed of three shots of 0.5 mL to be administered at 6-month interval. Individuals who are immunocompromised, whether congenital or acquired, cannot take the vaccine. People with known allergies to vaccine cannot also take the dengue vaccine. 

Based on the efficacy studies done in the Asia and Latin America, the efficacy of the dengue vaccine is 56.5% according to the study in Asia. It means that if you take the dengue vaccine, there is A 56.5% probability that you will not get the disease. There is also a reduction in the hospitalization due to dengue infection by 67.5% and 80% reduction rate in the severity of the dengue infection. This means that even though you take the dengue vaccine, you have around 50% chance of still getting dengue infection but lower probability that you will be hospitalized and get severe complications. There are several adverse reactions reported such as fever, headache, muscle pain, weakness, redness and swelling.

The major challenge with this vaccine is the level of efficacy which is quite low. Although Dr. Ong-Lim said that World Health Organization is already happy with the 56.5% efficacy. Their actual target is only around 30% reduction in dengue cases. My only concern with the studies on dengue vaccine is the result on the annual incidence ratio of dengue infection (severity and hospitalization) of the vaccinated and non-vaccinated group. The data presented, which I do not have a copy, has a very close value with large error bars that overlap with each other. This means that the data are highly spread and that the incidence in the vaccinated and non-vaccinated groups almost overlap. Another issue is the cost of the vaccine which is around 15,000 for the complete shots. For poor Filipinos who are struggling to make both ends meet, struggling to feed their families everyday, encouraging them to avail a vaccine which is this costly is very challenging. 

Improving the Influenza Control with Quadrivalent Influenza Vaccines

The next speaker was Dr. Mari Rose delos Reyes, president of the Philippine Society for Microbiology and Infectious disease. She talked about improving the influenza control with Quadrivalent Influenza Vaccines. Influenza is th 6th most common cause of mortality in the Philippines. 1/100 Filipinos get sick because of influenza every year. The problem with influenza is that the vaccine targets, hemagglutinin and neuraminidase, are genetically diverse and are capable of antigenic drift and antigenic shift. It means that the vaccine targets for influenza virus changes from time to time. This is why influenza vaccine is being updated annually. Right now, there are still no universal and genetically conserved vaccine target which is why we still need to get vaccinated annually to be protected from influenza.

I learned new things about influenza during the talk of Dr. delos Reyes. She shared to us that influenza virus is on of the most common viral cause of exacerbation of chronic obstructive pulmonary disorder. COPD includes emphysema, asthma and chronic bronchitis. She also said that influenza is a dual risk for diabetic patients because of decreased immune functions such as decreased intracellular killing, decreased immune cell trafficking and decreased phagocytosis. Diabetics are six times more likely to be hospitalized due to influenza and they are three times more likely to die because of influenza and pneumonia. Influenza is also a risk factor for cardiovascular diseases because it incresases proinflammatory and prothrombic cytokines, it causes endothelial dysfunction, increased plasma viscosity, tachycardia, and the release of endogenous catecholamines resulting to arrythmia. 

The quadrivalent influenza vaccine is composed the strains H1N1, H3N2, B/Victoria and B/Yamagata. The license for this vaccine was approved in the United States last July 2013 for use in persons six months of age and beyond. I think the vaccine is already available in the Philippines and it is distributed by the Sanofi Pasteur. Dr delos Reyes said that the best time to be vaccinated with influenza vaccine is before July since the peak season for getting influenza infection is July to October.

Updates and Strategies on Healthcare Worker Vaccination

The last speaker was Dr. Regina Berba, chairman of the Section of Infectious Disease and Tropical Medicine at the Philippine General Hospital. Dr. Berba talked about the recommended immunization for Filipino healthcare workers. Included in the highly recommended immunization were hepatitis B which is a major infectious hazard for healthcare workers, influenza, MMR, varicella, tetanus, diphteria and pertussis. Pneumococcal vaccine is also recommended while rabies vaccine and menigococcal vaccine are recommended only for selected healthcare workers who are at higher risk for these two diseases. If you want to know more about the recommended immunization for healthcare workers, please go to this link.

Dr. Berba mentioned a question regarding the cost of immunization for healthcare workers. Who should shoulder the cost of immunization, the healthcare workers or the institution? Hopefully, the institutions will shoulder the immunization costs of the healthcare professionals. Dr. Berba also mentioned that the utility persons from PhilCare working in Philippine General Hospital are not covered by the recommended immunization. I hope PGH will do something about this because these people are somehow also at risk of getting diseases because of their exposure in the hospital.

Before the forum ended, I asked Dr. Berba whether PGH allows patients with Hepatitis B infection to still work at the hospital. She said that they still allow but it is important that the person is undergoing treatment and the viral load is at the acceptable level to avoid transmission of infection. It is good to know that PGH does not discriminate people with hepatitis infection.

Challenge for Healthcare Workers
All of us want to do everything possible to make sure that we are healthy and protected from all preventable diseases. Vaccination is the best way to do this. Vaccination led to a dramatic decline in the number of infectious diseases in the Philippines. It is revolutionary and game changes in the field of medicine. Vaccination is not just to prevent yourself from getting diseases. It also prevents the spread and transmission of infectious diseases in the community. It is also a public commitment to the whole community to protect each other from getting the disease. As future healthcare professional, we are tasked to inform the public about the benefits of immunization. Let us altogether break all the misconceptions about vaccination.

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