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Follow these scientists working to get us safe and effective Covid vaccines. Ask them anything.

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These volunteers are making short videos on TikTok and Instagram to explain their part in the vaccine effort.


Dr Natalia Pasternak

Natalia is a microbiologist specialising in molecular genetics of bacteria. She currently works as a visiting researcher at the University of Sao Paolo, at the Vaccine Development Laboratory. She is the Director-President of the Instituto Questão de Ciência (“a question of science”) and an outspoken advocate for scientific thought in public life. She is a columnist for the newspaper “O Globo” and is a regular media commentator on Covid-19 in Brazil.


Andrea Mazzella

Dr Andrea Mazzella, MRCP (UK), is a Research Physician working in the NIHR Guy’s and St Thomas’ Biomedical Research Centre, and one of the investigators of three Phase III clinical trials investigating the Janssen, Novavax and Oxford/AstraZeneca vaccines for Covid-19. His role involves discussing the trials with volunteers, assessing their eligibility and conducting follow-up and pharmacovigilance with hundreds of trial participants.

After qualifying from medical school in Italy with an Erasmus exchange programme in Spain, Andrea moved to England to work as a doctor in the NHS. Once he completed Core Medical Training, he studied at London School of Hygiene and Tropical Medicine for a master’s degree in Epidemiology. It was during this year that the COVID-19 pandemic unfolded; he graduated and decided to join the team of researchers working on COVID-19 vaccine clinical trials.

Andrea grew up on a tiny island in the Mediterranean and loves returning home and sailing. He has a geeky passion for linguistics and is powered by dark chocolate and nonna’s struffoli.


Natali Serafin

Natali Serafin a research scientist working at the Vaccine and Infectious Disease Analytics (VIDA) research unit in South Africa. Natali’s expertise includes project management, epidemiology, and clinical medicine. She is currently managing a sentinel Covid-19 surveillance taking place at Chris Hani Baragwanath Academic Hospital in Soweto.


Jaqueline Goes de Jesus

Jaqueline Goes de Jesus is a biomedical scientist, in charge of the genetic sequencing of the new coronavirus in the first cases of Covid-19 in Latin America. She is currently working as a fellow at The São Paulo Research Foundation (FAPESP), as part of her post-doctorate at the São Paulo Institute of Tropical Medicine – University of São Paulo (IMT-USP), within the Brazil-UK Centre for Arbovirus Discovery, Diagnosis, Genomics and Epidemiology (CADDE). Jaqueline also carries out research in the field of the following emerging arboviruses: ZIKV, DENV, CHIKV, YFV, ORV and MAYV.


Dr Paul Ian Cross

Dr Paul Ian Cross is a subject matter expert in clinical trials at the National Institute of Health Research (NIHR) in England. Paul leads on the development of learning materials for doctors, nurses, researchers and scientists involved in the research response to Covid-19 and is also a clinical trials auditor. He has a background in Microbiology and completed his Master’s degree and PhD at Cardiff University. Paul is involved in several science communication projects across healthcare and STEM (science, technology, engineering, mathematics) education. Paul’s passion is writing STEM-inspired books and creating STEM content to introduce children and their families to the wonders of science.


Julio Sempere

Julio Sempere is a Biochemist and Microbiologist working for the National Centre for Microbiology, Instituto de Salud Carlos III, based in Madrid.

Julio works in the Spanish Pneumococcal Reference Laboratory, in the Vaccine Preventable Bacterial Diseases Unit, evaluating new vaccine serotypes of the pneumococcus and the impact of vaccines in invasive pneumococcal disease. Julio researches bacteria biofilms, approaching new treatments against antibiotic resistant bacteria, and studies the interaction of pathogens with the immune system. His interests are in vaccines, clinical microbiology and immunology. 

Julio is a Madrilenian (born and bred in Madrid) and since watching Grey’s Anatomy, he’s wanted to become a scientist. Julio also enjoys cycling and running, and before the pandemic, he used to love going to the gym.


Wasim Syed

Wasim A. P. Syed is a Pharmacy undergraduate student at the Ribeirão Preto School of Pharmaceutical Sciences, University of São Paulo. Currently, he has a Scientific Initiation scholarship from The Brazilian National Council for Scientific and Technological Development (CNPq) and is studying the human TMPRSS2 protein, involved in the SARS-CoV-2 virus infection process. Wasim is also a science communicator at Vidya Academics and União Pró-Vacina where he carries out projects that fight fake news, especially around Covid-19 and vaccines.


Daniela Ferreira

Daniela Ferreira is a Professor of Vaccinology and the Head of the Department of Clinical Sciences at Liverpool School of Tropical Medicine, in the United Kingdom, one of the centers that verify the effectiveness of the Covid-19 vaccine developed by Oxford. She currently leads several clinical studies for the development of vaccines against pneumonia and, recently, against the new Coronavirus.

Daniela has a Bachelor in Biological Sciences (2005) and a PhD in Immunology and Biotechnology (2009),both from the University of São Paulo, Brazil. From 2001 to 2009, she worked on the development of new vaccines against pneumococcus (the bacterium responsible for causing diseases such as meningitis, bacterial pneumonia and otitis media) at the Butantan Institute, in São Paulo. 

During her PhD, she was awarded the Robert Austrian Research Award in Pneumococcal Vaccinology sponsored by the American pharmaceutical company Wyeth, to develop new mucosal vaccines. Daniela has published over 80 scientific articles on respiratory infections and vaccines and leads a £11M portfolio of clinical studies.



Follow the people working on all aspects of science that will make these coronavirus vaccines safe and effective


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Dr Tim Mastro


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Ritudhwaj Tiwari


Paolo Bonanni


Samantha Vanderslott


Vipin M. Vashishtha


Dr. Krutika Kuppalli


Institute for Health Metrics and Evaluation


Majdi Sabahelzain


Dr. Angela Rasmussen


Heidi Larson


Naveen Thacker


You can help too

Thousands of volunteers around the world are signing up to help trial these vaccines to make sure they’re safe and effective.

Find a trial near you


Team Halo is an effort to support and celebrate the inspiring collaboration between scientists all over the world to help us end this pandemic with safe and effective vaccines.

The ‘halo’ represents the ring of connected science that circles the globe.

All participation is voluntary. If you’re involved in the vaccine search and would like to be listed on this site, please get in touch.

Team Halo was established in partnership with the The Vaccine Confidence Project at the University of London’s school of Hygiene and Tropical Medicine. It is proud to collaborate with the UN Verified Initiative and Gavi, the Vaccine Alliance. Support is provided by Luminate, IKEA Foundation and the Global Challenges Foundation.